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SEA · 2026 transactions
Data through 2026-10-03
| Date | Player | Type | Detail |
|---|---|---|---|
| Sep 25 | Andrés Muñoz | Status Change | Seattle Mariners placed RHP Andrés Muñoz on the 15-day injured list. Right knee inflammation. |
| Sep 25 | Troy Taylor | Recalled | Seattle Mariners recalled RHP Troy Taylor from Tacoma Rainiers. |
| Sep 24 | Brock Rodden | Status Change | Seattle Mariners placed SS Brock Rodden on the 10-day injured list retroactive to September 23, 2026. Left patella tendon inflammation. |
| Sep 24 | Leo Rivas | Recalled | Seattle Mariners recalled 3B Leo Rivas from Tacoma Rainiers. |
| Sep 16 | Julio Rodríguez | Number Change | CF Julio Rodríguez changed number to 44. |
| Sep 16 | J.P. Crawford | Number Change | SS J.P. Crawford changed number to 3. |
| Sep 15 | Julio Rodríguez | Number Change | CF Julio Rodríguez changed number to 21. |
| Sep 15 | J.P. Crawford | Number Change | SS J.P. Crawford changed number to 21. |
| Sep 11 | Stuart Fairchild | Outrighted | Seattle Mariners sent CF Stuart Fairchild outright to Tacoma Rainiers. |
| Sep 8 | Stuart Fairchild | Designated for Assignment | Seattle Mariners designated CF Stuart Fairchild for assignment. |
| Sep 8 | Troy Taylor | Optioned | Seattle Mariners optioned RHP Troy Taylor to Tacoma Rainiers. |
| Sep 8 | Hoby Milner | Status Change | Seattle Mariners activated LHP Hoby Milner. |
| Sep 8 | Victor Robles | Status Change | Seattle Mariners activated RF Victor Robles. |
| Sep 6 | Patrick Wisdom | Optioned | Seattle Mariners optioned 3B Patrick Wisdom to Tacoma Rainiers. |
| Sep 6 | Michael Arroyo | Selected | Seattle Mariners selected the contract of SS Michael Arroyo from Tacoma Rainiers. |
| Sep 6 | Nick Davila | Status Change | Seattle Mariners transferred RHP Nick Davila from the 15-day injured list to the 60-day injured list. SC joint sprain. |
| Sep 4 | Troy Taylor | Recalled | Seattle Mariners recalled RHP Troy Taylor from Tacoma Rainiers. |
| Sep 3 | Brennen Davis | Status Change | Seattle Mariners placed CF Brennen Davis on the 60-day injured list. Left hamstring strain. |
| Sep 3 | Brennen Davis | Recalled | Seattle Mariners recalled CF Brennen Davis from Tacoma Rainiers. |
| Sep 3 | Stuart Fairchild | Selected | Seattle Mariners selected the contract of CF Stuart Fairchild from Tacoma Rainiers. |
| Sep 3 | Victor Robles | Status Change | RF Victor Robles roster status changed by Seattle Mariners. |
| Sep 3 | Nolan Kingham | Outrighted | Seattle Mariners sent RHP Nolan Kingham outright to Tacoma Rainiers. |
| Sep 3 | Connor Joe | Outrighted | Seattle Mariners sent RF Connor Joe outright to Tacoma Rainiers. |
| Sep 2 | Simeon Woods Richardson | Signed as Free Agent | Seattle Mariners signed free agent RHP Simeon Woods Richardson to a minor league contract. |
| Sep 1 | Nolan Kingham | Designated for Assignment | Seattle Mariners designated RHP Nolan Kingham for assignment. |
| Sep 1 | Connor Joe | Designated for Assignment | Seattle Mariners designated RF Connor Joe for assignment. |
| Sep 1 | Hoby Milner | Signed as Free Agent | Seattle Mariners signed free agent LHP Hoby Milner. |
| Sep 1 | Lazaro Montes | Selected | Seattle Mariners selected the contract of RF Lazaro Montes from Tacoma Rainiers. |
| Aug 31 | Colt Emerson | Status Change | Seattle Mariners transferred SS Colt Emerson from the 10-day injured list to the 60-day injured list. Left wrist tendon repair. |
| Aug 31 | Nick Davila | Status Change | Seattle Mariners placed RHP Nick Davila on the 15-day injured list. SC joint sprain. |
| Aug 31 | Cooper Criswell | Status Change | Seattle Mariners activated RHP Cooper Criswell from the 60-day injured list. |
| Aug 30 | Emerson Hancock | Status Change | Seattle Mariners placed RHP Emerson Hancock on the 15-day injured list retroactive to August 29, 2026. Left abductor strain. |
| Aug 30 | Nick Davila | Recalled | Seattle Mariners recalled RHP Nick Davila from Tacoma Rainiers. |
| Aug 25 | J.P. Crawford | Status Change | Seattle Mariners activated SS J.P. Crawford from the 10-day injured list. |
| Aug 25 | Leo Rivas | Optioned | Seattle Mariners optioned 3B Leo Rivas to Tacoma Rainiers. |
| Aug 24 | Jhonathan Díaz | Outrighted | Seattle Mariners sent LHP Jhonathan Díaz outright to Tacoma Rainiers. |
| Aug 23 | Brendan Donovan | Status Change | Seattle Mariners placed 3B Brendan Donovan on the 7-day injured list retroactive to August 22, 2026. Concussion. |
| Aug 23 | Patrick Wisdom | Recalled | Seattle Mariners recalled 3B Patrick Wisdom from Tacoma Rainiers. |
| Aug 22 | Cooper Criswell | Assigned | Seattle Mariners sent RHP Cooper Criswell on a rehab assignment to Tacoma Rainiers. |
| Aug 22 | Cooper Criswell | Assigned | Seattle Mariners sent RHP Cooper Criswell on a rehab assignment to Tacoma Rainiers. |
| Aug 22 | Jhonathan Díaz | Designated for Assignment | Seattle Mariners designated LHP Jhonathan Díaz for assignment. |
| Aug 22 | Kade Anderson | Selected | Seattle Mariners selected the contract of LHP Kade Anderson from Arkansas Travelers. |
| Aug 21 | Carlos Vargas | Status Change | Seattle Mariners activated RHP Carlos Vargas from the 60-day injured list. |
| Aug 21 | Matt Brash | Status Change | Seattle Mariners transferred RHP Matt Brash from the 15-day injured list to the 60-day injured list. Right lat strain. |
| Aug 21 | Nick Davila | Optioned | Seattle Mariners optioned RHP Nick Davila to Tacoma Rainiers. |
| Aug 20 | J.P. Crawford | Assigned | Seattle Mariners sent SS J.P. Crawford on a rehab assignment to Tacoma Rainiers. |
| Aug 19 | Luke Raley | Status Change | Seattle Mariners transferred RF Luke Raley from the 10-day injured list to the 60-day injured list. Left forearm strain. |
| Aug 19 | Josh Simpson | Optioned | Seattle Mariners optioned LHP Josh Simpson to Tacoma Rainiers. |
| Aug 19 | Jhonathan Díaz | Selected | Seattle Mariners selected the contract of LHP Jhonathan Díaz from Tacoma Rainiers. |
| Aug 18 | Andy Ibáñez | Signed as Free Agent | Seattle Mariners signed free agent 2B Andy Ibáñez to a minor league contract. |
| Aug 15 | Troy Watson | Optioned | Seattle Mariners optioned RHP Troy Watson to Tacoma Rainiers. |
| Aug 15 | Troy Watson | Claimed Off Waivers | Seattle Mariners claimed RHP Troy Watson off waivers from Detroit Tigers. |
| Aug 14 | Willie MacIver | Optioned | Seattle Mariners optioned C Willie MacIver to Tacoma Rainiers. |
| Aug 14 | Colt Emerson | Status Change | Seattle Mariners placed SS Colt Emerson on the 10-day injured list. Left wrist tendon inflammation. |
| Aug 14 | Brock Rodden | Selected | Seattle Mariners selected the contract of 2B Brock Rodden from Tacoma Rainiers. |
| Aug 13 | Lael Lockhart | Signed as Free Agent | Seattle Mariners signed free agent LHP Lael Lockhart to a minor league contract. |
| Aug 12 | Scott Effross | Signed as Free Agent | Seattle Mariners signed free agent RHP Scott Effross to a minor league contract. |
| Aug 12 | Willie MacIver | Claimed Off Waivers | Seattle Mariners claimed C Willie MacIver off waivers from Toronto Blue Jays. |
| Aug 11 | Conor Larkin | Signed as Free Agent | Seattle Mariners signed free agent RHP Conor Larkin to a minor league contract. |
| Aug 11 | Gabe Speier | Status Change | Seattle Mariners activated LHP Gabe Speier. |
| Aug 11 | Carlos Vargas | Assigned | Seattle Mariners sent RHP Carlos Vargas on a rehab assignment to Tacoma Rainiers. |
| Aug 10 | Nolan Kingham | Claimed Off Waivers | Seattle Mariners claimed RHP Nolan Kingham off waivers from Texas Rangers. |
| Aug 8 | Gabe Speier | Status Change | LHP Gabe Speier roster status changed by Seattle Mariners. |
| Aug 8 | Carlos Vargas | Assigned | Seattle Mariners sent RHP Carlos Vargas on a rehab assignment to Everett AquaSox. |
| Aug 8 | Stuart Fairchild | Signed as Free Agent | Seattle Mariners signed free agent CF Stuart Fairchild to a minor league contract. |
| Aug 8 | Carlos Vargas | Assigned | Seattle Mariners sent RHP Carlos Vargas on a rehab assignment to Everett AquaSox. |
| Aug 7 | Stuart Fairchild | Outrighted | Seattle Mariners sent CF Stuart Fairchild outright to Tacoma Rainiers. |
| Aug 7 | Cole Wilcox | Status Change | Seattle Mariners placed RHP Cole Wilcox on the 15-day injured list. Left oblique strain. |
| Aug 7 | Nick Davila | Recalled | Seattle Mariners recalled RHP Nick Davila from Tacoma Rainiers. |
| Aug 5 | Seth Shuman | Signed as Free Agent | Seattle Mariners signed free agent RHP Seth Shuman to a minor league contract. |
| Aug 4 | Stuart Fairchild | Designated for Assignment | Seattle Mariners designated CF Stuart Fairchild for assignment. |
| Aug 4 | Rob Refsnyder | Released | Seattle Mariners released DH Rob Refsnyder. |
| Aug 4 | Mitch Garver | Released | Seattle Mariners released C Mitch Garver. |
| Aug 4 | Jhonny Pereda | Recalled | Seattle Mariners recalled C Jhonny Pereda from Tacoma Rainiers. |
| Aug 4 | Seranthony Domínguez | Status Change | Seattle Mariners activated RHP Seranthony Domínguez. |
| Aug 4 | Taylor Ward | Status Change | Seattle Mariners activated LF Taylor Ward. |
| Aug 4 | Brendan Donovan | Status Change | Seattle Mariners activated 3B Brendan Donovan from the 10-day injured list. |
| Aug 3 | Taylor Ward | Status Change | LF Taylor Ward roster status changed by Seattle Mariners. |
| Aug 3 | Taylor Ward | Trade | Baltimore Orioles traded LF Taylor Ward to Seattle Mariners for RHP Alex Hoppe, RHP Brock Moore and RHP Harrison Kreiling. |
| Aug 2 | Josh Simpson | Recalled | Seattle Mariners recalled LHP Josh Simpson from Tacoma Rainiers. |
| Aug 2 | Buddy Kennedy | Claimed Off Waivers | San Francisco Giants claimed 1B Buddy Kennedy off waivers from Seattle Mariners. |
| Aug 2 | Luis Castillo | Trade | Seattle Mariners traded RHP Luis Castillo to Chicago White Sox for RHP Seranthony Domínguez, C Boston Smith, RF Nolan Jones and cash. |
| Aug 1 | Luke Raley | Status Change | Seattle Mariners placed RF Luke Raley on the 10-day injured list retroactive to July 31, 2026. Left forearm strain. |
| Aug 1 | Stuart Fairchild | Selected | Seattle Mariners selected the contract of CF Stuart Fairchild from Tacoma Rainiers. |
| Jul 31 | Leo Rivas | Recalled | Seattle Mariners recalled 3B Leo Rivas from Tacoma Rainiers. |
| Jul 31 | J.P. Crawford | Status Change | Seattle Mariners placed SS J.P. Crawford on the 10-day injured list retroactive to July 30, 2026. Left wrist inflammation. |
| Jul 28 | Rob Refsnyder | Status Change | Seattle Mariners activated DH Rob Refsnyder from the 10-day injured list. |
| Jul 28 | Buddy Kennedy | Designated for Assignment | Seattle Mariners designated 1B Buddy Kennedy for assignment. |
| Jul 28 | Brendan Donovan | Assigned | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Tacoma Rainiers. |
| Jul 27 | Similien Senatus | Signed as Free Agent | Seattle Mariners signed free agent RHP Similien Senatus to a minor league contract. |
| Jul 26 | Nick Davila | Optioned | Seattle Mariners optioned RHP Nick Davila to Tacoma Rainiers. |
| Jul 26 | Alex Hoppe | Recalled | Seattle Mariners recalled RHP Alex Hoppe from Tacoma Rainiers. |
| Jul 21 | Miles Mastrobuoni | Outrighted | Seattle Mariners sent 3B Miles Mastrobuoni outright to Tacoma Rainiers. |
| Jul 21 | Isaac Thornton | Signed as Free Agent | Seattle Mariners signed free agent RHP Isaac Thornton to a minor league contract. |
| Jul 21 | Jake Harvey | Signed as Free Agent | Seattle Mariners signed free agent C Jake Harvey to a minor league contract. |
| Jul 21 | Jacob Galloway | Signed as Free Agent | Seattle Mariners signed free agent C Jacob Galloway to a minor league contract. |
| Jul 21 | Kyle Boylston | Signed as Free Agent | Seattle Mariners signed free agent OF Kyle Boylston to a minor league contract. |
| Jul 21 | Ace Reese | Signed | Seattle Mariners signed 3B Ace Reese. |
| Jul 21 | Brendan Donovan | Assigned | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Everett AquaSox. |
| Jul 18 | Rob Refsnyder | Assigned | Seattle Mariners sent DH Rob Refsnyder on a rehab assignment to Tacoma Rainiers. |
| Jul 18 | Rob Refsnyder | Assigned | Seattle Mariners sent DH Rob Refsnyder on a rehab assignment to Tacoma Rainiers. |
| Jul 18 | Julio Rodríguez | Status Change | Seattle Mariners activated CF Julio Rodríguez from the 7-day injured list. |
| Jul 18 | Miles Mastrobuoni | Designated for Assignment | Seattle Mariners designated 3B Miles Mastrobuoni for assignment. |
| Jul 17 | Henry Kaczmar | Signed as Free Agent | Seattle Mariners signed free agent SS Henry Kaczmar to a minor league contract. |
| Jul 17 | Connor Marshburn | Signed | Seattle Mariners signed RHP Connor Marshburn. |
| Jul 17 | Connor Marshburn | Signed | Seattle Mariners signed RHP Connor Marshburn. |
| Jul 17 | Anthony Treto | Signed | Seattle Mariners signed RHP Anthony Treto. |
| Jul 17 | Wyatt Queen | Signed | Seattle Mariners signed RHP Wyatt Queen. |
| Jul 17 | Chris Diaz | Signed | Seattle Mariners signed RHP Chris Diaz. |
| Jul 17 | Eric Jeon | Signed | Seattle Mariners signed 2B Eric Jeon. |
| Jul 17 | Charlie Sutherland | Signed | Seattle Mariners signed OF Charlie Sutherland. |
| Jul 17 | Chris Torres | Signed | Seattle Mariners signed LHP Chris Torres. |
| Jul 17 | Drew Whalen | Signed | Seattle Mariners signed RHP Drew Whalen. |
| Jul 17 | Mason Eckelman | Signed | Seattle Mariners signed C Mason Eckelman. |
| Jul 17 | Matthew Matthijs | Signed | Seattle Mariners signed RHP Matthew Matthijs. |
| Jul 17 | Ryan Wynn | Signed | Seattle Mariners signed SS Ryan Wynn. |
| Jul 17 | Michael Petite | Signed | Seattle Mariners signed OF Michael Petite. |
| Jul 17 | Henry Ford | Signed | Seattle Mariners signed 3B Henry Ford. |
| Jul 17 | Hayden Yost | Signed | Seattle Mariners signed OF Hayden Yost. |
| Jul 17 | Trevor Lucas | Signed | Seattle Mariners signed 3B Trevor Lucas. |
| Jul 17 | Nathan Taylor | Signed | Seattle Mariners signed RHP Nathan Taylor. |
| Jul 17 | Jake Brown | Signed | Seattle Mariners signed OF Jake Brown. |
| Jul 17 | Brendan Donovan | Assigned | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Tacoma Rainiers. |
| Jul 17 | Brendan Donovan | Assigned | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Tacoma Rainiers. |
| Jul 15 | Brendan Donovan | Assigned | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to ACL Mariners. |
| Jul 11 | Carson Taylor | Trade | Seattle Mariners traded 1B Carson Taylor to Atlanta Braves. |
| Jul 7 | Mario Vasquez | Signed as Free Agent | Seattle Mariners signed free agent RHP Mario Vasquez to a minor league contract. |
| Jul 7 | Stuart Fairchild | Assigned | CF Stuart Fairchild assigned to ACL Mariners from Seattle Mariners. |
| Jul 5 | Stuart Fairchild | Status Change | CF Stuart Fairchild roster status changed by Seattle Mariners. |
| Jul 5 | Stuart Fairchild | Signed as Free Agent | Seattle Mariners signed free agent CF Stuart Fairchild to a minor league contract. |
| Jul 3 | Miles Mastrobuoni | Selected | Seattle Mariners selected the contract of 3B Miles Mastrobuoni from Tacoma Rainiers. |
| Jul 3 | Julio Rodríguez | Status Change | Seattle Mariners placed CF Julio Rodríguez on the 7-day injured list. Concussion. |
| Jul 3 | Cooper Criswell | Status Change | Seattle Mariners transferred RHP Cooper Criswell from the 15-day injured list to the 60-day injured list. Right shoulder strain. |
| Jun 30 | Josh Simpson | Optioned | Seattle Mariners optioned LHP Josh Simpson to Tacoma Rainiers. |
| Jun 30 | Cole Wilcox | Recalled | Seattle Mariners recalled RHP Cole Wilcox from Tacoma Rainiers. |
| Jun 29 | Rob Refsnyder | Status Change | Seattle Mariners placed DH Rob Refsnyder on the 10-day injured list retroactive to June 27, 2026. Right knee inflammation. |
| Jun 29 | — | Trade | San Francisco Giants traded 1B Buddy Kennedy to Seattle Mariners for cash. |
| Jun 27 | Josh Simpson | Recalled | Seattle Mariners recalled LHP Josh Simpson from Tacoma Rainiers. |
| Jun 27 | Alex Hoppe | Optioned | Seattle Mariners optioned RHP Alex Hoppe to Tacoma Rainiers. |
| Jun 25 | Miles Mastrobuoni | Outrighted | Seattle Mariners sent 3B Miles Mastrobuoni outright to Tacoma Rainiers. |
| Jun 23 | Randy Arozarena | Status Change | Seattle Mariners activated LF Randy Arozarena from the 10-day injured list. |
| Jun 23 | Connor Joe | Optioned | Seattle Mariners optioned RF Connor Joe to Tacoma Rainiers. |
| Jun 20 | Curtis Washington Jr. | Outrighted | Seattle Mariners sent CF Curtis Washington Jr. outright to Everett AquaSox. |
| Jun 19 | Weston Wilson | Selected | Seattle Mariners selected the contract of 3B Weston Wilson from Tacoma Rainiers. |
| Jun 19 | Miles Mastrobuoni | Designated for Assignment | Seattle Mariners designated 3B Miles Mastrobuoni for assignment. |
| Jun 18 | Ferny Barreda | Signed as Free Agent | Seattle Mariners signed free agent RHP Ferny Barreda to a minor league contract. |
| Jun 18 | Adalberto Vallenilla | Signed as Free Agent | Seattle Mariners signed free agent RHP Adalberto Vallenilla to a minor league contract. |
| Jun 17 | — | Trade | Seattle Mariners traded RHP Randy Dobnak to Kansas City Royals for cash. |
| Jun 17 | Curtis Washington Jr. | Optioned | Seattle Mariners optioned CF Curtis Washington Jr. to Everett AquaSox. |
| Jun 17 | Connor Joe | Recalled | Seattle Mariners recalled RF Connor Joe from Tacoma Rainiers. |
| Jun 16 | Will Wilson | Status Change | Seattle Mariners transferred 3B Will Wilson from the 10-day injured list to the 60-day injured list. Left thumb fracture. |
| Jun 16 | Randy Arozarena | Status Change | Seattle Mariners placed LF Randy Arozarena on the 10-day injured list retroactive to June 13, 2026. Left hamstring strain. |
| Jun 16 | Curtis Washington Jr. | Selected | Seattle Mariners selected the contract of CF Curtis Washington Jr. from Everett AquaSox. |
| Jun 16 | Cal Raleigh | Status Change | Seattle Mariners activated C Cal Raleigh from the 10-day injured list. |
| Jun 16 | J.P. Crawford | Status Change | Seattle Mariners activated SS J.P. Crawford from the 10-day injured list. |
| Jun 16 | Jhonny Pereda | Optioned | Seattle Mariners optioned C Jhonny Pereda to Tacoma Rainiers. |
| Jun 15 | Domingo Gonzalez | Outrighted | Seattle Mariners sent RHP Domingo Gonzalez outright to Tacoma Rainiers. |
| Jun 15 | Patrick Wisdom | Optioned | Seattle Mariners optioned 3B Patrick Wisdom to Tacoma Rainiers. |
| Jun 15 | Yosver Zulueta | Trade | Seattle Mariners traded RHP Yosver Zulueta to Chicago Cubs for cash. |
| Jun 14 | Weston Wilson | Signed as Free Agent | Seattle Mariners signed free agent 3B Weston Wilson to a minor league contract. |
| Jun 13 | Michael Plassmeyer | Signed as Free Agent | Seattle Mariners signed free agent LHP Michael Plassmeyer to a minor league contract. |
| Jun 12 | Connor Wilford | Acquired | Seattle Mariners acquired RHP Connor Wilford from the Lexington Legends of the Atlantic League. |
| Jun 11 | Michael Rucker | Selected | Seattle Mariners selected the contract of RHP Michael Rucker from Tacoma Rainiers. |
| Jun 11 | Domingo Gonzalez | Designated for Assignment | Seattle Mariners designated RHP Domingo Gonzalez for assignment. |
| Jun 10 | Carson Fulmer | Trade | Pittsburgh Pirates traded RHP Carson Fulmer to Seattle Mariners for cash. |
| Jun 10 | Matt Brash | Status Change | Seattle Mariners placed RHP Matt Brash on the 15-day injured list retroactive to June 9, 2026. Right lat strain. |
| Jun 10 | Ryan Bliss | Optioned | Seattle Mariners optioned 2B Ryan Bliss to Tacoma Rainiers. |
| Jun 10 | Yosver Zulueta | Designated for Assignment | Seattle Mariners designated RHP Yosver Zulueta for assignment. |
| Jun 10 | Domingo Gonzalez | Recalled | Seattle Mariners recalled RHP Domingo Gonzalez from Tacoma Rainiers. |
| Jun 10 | Miles Mastrobuoni | Status Change | Seattle Mariners activated 3B Miles Mastrobuoni from the 60-day injured list. |
| Jun 9 | Will Wilson | Assigned | Seattle Mariners sent 3B Will Wilson on a rehab assignment to Tacoma Rainiers. |
| Jun 9 | Cooper Criswell | Status Change | Seattle Mariners placed RHP Cooper Criswell on the 15-day injured list. Right shoulder strain. |
| Jun 9 | Nick Davila | Recalled | Seattle Mariners recalled RHP Nick Davila from Tacoma Rainiers. |
| Jun 9 | Cal Raleigh | Assigned | Seattle Mariners sent C Cal Raleigh on a rehab assignment to Tacoma Rainiers. |
| Jun 8 | J.P. Crawford | Status Change | Seattle Mariners placed SS J.P. Crawford on the 10-day injured list retroactive to June 6, 2026. Right hand contusion. |
| Jun 8 | Ryan Bliss | Recalled | Seattle Mariners recalled 2B Ryan Bliss from Tacoma Rainiers. |
| Jun 7 | Cal Raleigh | Assigned | Seattle Mariners sent C Cal Raleigh on a rehab assignment to Everett AquaSox. |
| Jun 5 | Will Wilson | Assigned | Seattle Mariners sent 3B Will Wilson on a rehab assignment to Everett AquaSox. |
| Jun 5 | Magz German | Signed as Free Agent | Seattle Mariners signed free agent SS Magz German to a minor league contract. |
| Jun 4 | Caleb Franzen | Signed as Free Agent | Seattle Mariners signed free agent LHP Caleb Franzen to a minor league contract. |
| May 27 | Miles Mastrobuoni | Assigned | Seattle Mariners sent 3B Miles Mastrobuoni on a rehab assignment to Tacoma Rainiers. |
| May 27 | Miles Mastrobuoni | Assigned | Seattle Mariners sent 3B Miles Mastrobuoni on a rehab assignment to Tacoma Rainiers. |
| May 26 | Nick Davila | Optioned | Seattle Mariners optioned RHP Nick Davila to Tacoma Rainiers. |
| May 26 | Gabe Speier | Status Change | Seattle Mariners activated LHP Gabe Speier from the 15-day injured list. |
| May 25 | Miles Mastrobuoni | Assigned | Seattle Mariners sent 3B Miles Mastrobuoni on a rehab assignment to ACL Mariners. |
| May 23 | Gabe Speier | Assigned | Seattle Mariners sent LHP Gabe Speier on a rehab assignment to Tacoma Rainiers. |
| May 22 | Victor Robles | Status Change | Seattle Mariners activated RF Victor Robles from the 10-day injured list. |
| May 22 | Connor Joe | Optioned | Seattle Mariners optioned RF Connor Joe to Tacoma Rainiers. |
| May 20 | Gabe Speier | Assigned | Seattle Mariners sent LHP Gabe Speier on a rehab assignment to Everett AquaSox. |
| May 20 | Robinson Ortiz | Optioned | Seattle Mariners optioned LHP Robinson Ortiz to Tacoma Rainiers. |
| May 20 | Matt Brash | Status Change | Seattle Mariners activated RHP Matt Brash from the 15-day injured list. |
| May 20 | Gabe Speier | Assigned | Seattle Mariners sent LHP Gabe Speier on a rehab assignment to Everett AquaSox. |
| May 18 | Brennen Davis | Optioned | Seattle Mariners optioned CF Brennen Davis to Tacoma Rainiers. |
| May 18 | Brennen Davis | Selected | Seattle Mariners selected the contract of CF Brennen Davis from Tacoma Rainiers. |
| May 18 | Leo Rivas | Optioned | Seattle Mariners optioned 3B Leo Rivas to Tacoma Rainiers. |
| May 18 | Domingo Gonzalez | Optioned | Seattle Mariners optioned RHP Domingo Gonzalez to Tacoma Rainiers. |
| May 18 | Robinson Ortiz | Recalled | Seattle Mariners recalled LHP Robinson Ortiz from Tacoma Rainiers. |
| May 18 | Patrick Wisdom | Status Change | Seattle Mariners activated 1B Patrick Wisdom from the 10-day injured list. |
| May 17 | Brendan Donovan | Status Change | Seattle Mariners placed 3B Brendan Donovan on the 10-day injured list retroactive to May 16, 2026. Left groin muscle strain. |
| May 17 | Colt Emerson | Recalled | Seattle Mariners recalled SS Colt Emerson from Tacoma Rainiers. |
| May 14 | Matt Brash | Assigned | Seattle Mariners sent RHP Matt Brash on a rehab assignment to Tacoma Rainiers. |
| May 14 | Matt Brash | Assigned | Seattle Mariners sent RHP Matt Brash on a rehab assignment to Tacoma Rainiers. |
| May 14 | — | Trade | Seattle Mariners traded LHP José Suarez to Athletics for cash. |
| May 14 | Cal Raleigh | Status Change | Seattle Mariners placed C Cal Raleigh on the 10-day injured list. Right oblique strain. |
| May 14 | Josh Simpson | Optioned | Seattle Mariners optioned LHP Josh Simpson to Tacoma Rainiers. |
| May 14 | José A. Ferrer | Status Change | Seattle Mariners activated LHP José A. Ferrer from the paternity list. |
| May 14 | Jhonny Pereda | Recalled | Seattle Mariners recalled C Jhonny Pereda from Tacoma Rainiers. |
| May 13 | Bryce Miller | Status Change | Seattle Mariners activated RHP Bryce Miller from the 15-day injured list. |
| May 13 | José Suarez | Designated for Assignment | Seattle Mariners designated LHP José Suarez for assignment. |
| May 11 | José A. Ferrer | Status Change | Seattle Mariners placed LHP José A. Ferrer on the paternity list. |
| May 11 | Domingo Gonzalez | Recalled | Seattle Mariners recalled RHP Domingo Gonzalez from Tacoma Rainiers. |
| May 9 | Rhylan Thomas | Claimed Off Waivers | Houston Astros claimed LF Rhylan Thomas off waivers from Seattle Mariners. |
| May 8 | Scott Rouse | Signed as Free Agent | Seattle Mariners signed free agent RHP Scott Rouse to a minor league contract. |
| May 8 | Jhonny Pereda | Optioned | Seattle Mariners optioned C Jhonny Pereda to Tacoma Rainiers. |
| May 8 | Brendan Donovan | Status Change | Seattle Mariners activated 3B Brendan Donovan from the 10-day injured list. |
| May 7 | Dominic Castellano | Signed | Seattle Mariners signed LHP Dominic Castellano. |
| May 7 | Sam Whiting | Signed as Free Agent | Seattle Mariners signed free agent RHP Sam Whiting to a minor league contract. |
| May 6 | Cole Cheatham | Signed as Free Agent | Seattle Mariners signed free agent LHP Cole Cheatham to a minor league contract. |
| May 6 | Bryce Miller | Assigned | Seattle Mariners sent RHP Bryce Miller on a rehab assignment to Everett AquaSox. |
| May 5 | Brendan Donovan | Assigned | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Arkansas Travelers. |
| May 5 | Patrick Wisdom | Assigned | Seattle Mariners sent 1B Patrick Wisdom on a rehab assignment to Tacoma Rainiers. |
| May 5 | Brendan Donovan | Assigned | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Arkansas Travelers. |
| May 4 | Gabe Speier | Status Change | Seattle Mariners placed LHP Gabe Speier on the 15-day injured list retroactive to May 3, 2026. Left shoulder inflammation. |
| May 4 | Cole Wilcox | Optioned | Seattle Mariners optioned RHP Cole Wilcox to Tacoma Rainiers. |
| May 4 | José Suarez | Status Change | Seattle Mariners activated LHP José Suarez. |
| May 4 | Josh Simpson | Recalled | Seattle Mariners recalled LHP Josh Simpson from Tacoma Rainiers. |
| May 3 | Rhylan Thomas | Designated for Assignment | Seattle Mariners designated LF Rhylan Thomas for assignment. |
| May 3 | José Suarez | Claimed Off Waivers | Seattle Mariners claimed LHP José Suarez off waivers from Atlanta Braves. |
| May 3 | Victor Robles | Assigned | Seattle Mariners sent RF Victor Robles on a rehab assignment to Tacoma Rainiers. |
| May 2 | Will Wilson | Status Change | Seattle Mariners placed 3B Will Wilson on the 10-day injured list retroactive to April 30, 2026. Left thumb fracture. |
| May 2 | Jhonny Pereda | Recalled | Seattle Mariners recalled C Jhonny Pereda from Tacoma Rainiers. |
| May 2 | Josh Simpson | Optioned | Seattle Mariners optioned LHP Josh Simpson to Tacoma Rainiers. |
| May 2 | Nick Davila | Selected | Seattle Mariners selected the contract of RHP Nick Davila from Arkansas Travelers. |
| May 1 | Adam Smith | Contract Purchased | Seattle Mariners purchased contract of RHP Adam Smith. |
| May 1 | Matt Brash | Status Change | Seattle Mariners placed RHP Matt Brash on the 15-day injured list retroactive to April 30, 2026. Right lat inflammation. |
| May 1 | Josh Simpson | Recalled | Seattle Mariners recalled LHP Josh Simpson from Tacoma Rainiers. |
| Apr 30 | Bryce Miller | Assigned | Seattle Mariners sent RHP Bryce Miller on a rehab assignment to Tacoma Rainiers. |
| Apr 24 | Bryce Miller | Assigned | Seattle Mariners sent RHP Bryce Miller on a rehab assignment to Everett AquaSox. |
| Apr 24 | Casey Legumina | Trade | Seattle Mariners traded RHP Casey Legumina to Tampa Bay Rays for RHP Ty Cummings. |
| Apr 24 | Bryce Miller | Assigned | Seattle Mariners sent RHP Bryce Miller on a rehab assignment to Everett AquaSox. |
| Apr 22 | Nick Hull | Signed as Free Agent | Seattle Mariners signed free agent RHP Nick Hull to a minor league contract. |
| Apr 21 | Alex Hoppe | Recalled | Seattle Mariners recalled RHP Alex Hoppe from Tacoma Rainiers. |
| Apr 21 | Casey Legumina | Designated for Assignment | Seattle Mariners designated RHP Casey Legumina for assignment. |
| Apr 21 | Blas Castaño | Claimed Off Waivers | Colorado Rockies claimed RHP Blas Castaño off waivers from Seattle Mariners. |
| Apr 20 | Will Wilson | Selected | Seattle Mariners selected the contract of 3B Will Wilson from Tacoma Rainiers. |
| Apr 20 | Miles Mastrobuoni | Status Change | Seattle Mariners placed 3B Miles Mastrobuoni on the 60-day injured list. Right calf strain. |
| Apr 20 | Brendan Donovan | Status Change | Seattle Mariners placed 2B Brendan Donovan on the 10-day injured list retroactive to April 18, 2026. Left groin muscle strain. |
| Apr 18 | Bryce Miller | Assigned | Seattle Mariners sent RHP Bryce Miller on a rehab assignment to Tacoma Rainiers. |
| Apr 17 | Patrick Wisdom | Status Change | Seattle Mariners placed 1B Patrick Wisdom on the 10-day injured list retroactive to April 15, 2026. Left oblique strain. |
| Apr 17 | Rob Refsnyder | Status Change | Seattle Mariners activated RF Rob Refsnyder from the paternity list. |
| Apr 16 | Connor Joe | Status Change | Seattle Mariners activated RF Connor Joe. |
| Apr 16 | Dominic Canzone | Status Change | Seattle Mariners activated DH Dominic Canzone. |
| Apr 16 | Dominic Canzone | Number Change | RF Dominic Canzone changed number to 8. |
| Apr 16 | Randy Arozarena | Number Change | LF Randy Arozarena changed number to 56. |
| Apr 16 | Eduard Bazardo | Number Change | RHP Eduard Bazardo changed number to 83. |
| Apr 16 | Matt Brash | Number Change | RHP Matt Brash changed number to 47. |
| Apr 16 | José A. Ferrer | Number Change | LHP Jose A. Ferrer changed number to 45. |
| Apr 16 | Cooper Criswell | Number Change | RHP Cooper Criswell changed number to 88. |
| Apr 16 | Brendan Donovan | Number Change | 2B Brendan Donovan changed number to 33. |
| Apr 16 | J.P. Crawford | Number Change | SS J.P. Crawford changed number to 3. |
| Apr 16 | Luis Castillo | Number Change | RHP Luis Castillo changed number to 58. |
| Apr 16 | Mitch Garver | Number Change | C Mitch Garver changed number to 18. |
| Apr 16 | Casey Legumina | Number Change | RHP Casey Legumina changed number to 64. |
| Apr 16 | Connor Joe | Number Change | 1B Connor Joe changed number to 9. |
| Apr 16 | Logan Gilbert | Number Change | RHP Logan Gilbert changed number to 36. |
| Apr 16 | George Kirby | Number Change | RHP George Kirby changed number to 68. |
| Apr 16 | Emerson Hancock | Number Change | RHP Emerson Hancock changed number to 26. |
| Apr 16 | Josh Naylor | Number Change | 1B Josh Naylor changed number to 12. |
| Apr 16 | Cal Raleigh | Number Change | C Cal Raleigh changed number to 29. |
| Apr 16 | Andrés Muñoz | Number Change | RHP Andrés Muñoz changed number to 75. |
| Apr 16 | Rob Refsnyder | Number Change | RF Rob Refsnyder changed number to 30. |
| Apr 16 | Gabe Speier | Number Change | LHP Gabe Speier changed number to 55. |
| Apr 16 | Julio Rodríguez | Number Change | CF Julio Rodríguez changed number to 44. |
| Apr 16 | Leo Rivas | Number Change | 2B Leo Rivas changed number to 76. |
| Apr 16 | Luke Raley | Number Change | RF Luke Raley changed number to 20. |
| Apr 16 | Cole Wilcox | Number Change | RHP Cole Wilcox changed number to 43. |
| Apr 16 | Cole Young | Number Change | 2B Cole Young changed number to 2. |
| Apr 16 | Bryan Woo | Number Change | RHP Bryan Woo changed number to 22. |
| Apr 16 | Patrick Wisdom | Number Change | 1B Patrick Wisdom changed number to 35. |
| Apr 15 | Jesus Rondon | Signed as Free Agent | Seattle Mariners signed free agent RHP Jesus Rondon to a minor league contract. |
| Apr 15 | Luis Castillo | Number Change | RHP Luis Castillo changed number to 42. |
| Apr 15 | Cole Wilcox | Number Change | RHP Cole Wilcox changed number to 42. |
| Apr 15 | Cole Young | Number Change | 2B Cole Young changed number to 42. |
| Apr 15 | Casey Legumina | Number Change | RHP Casey Legumina changed number to 42. |
| Apr 15 | Brendan Donovan | Number Change | 2B Brendan Donovan changed number to 42. |
| Apr 15 | J.P. Crawford | Number Change | SS J.P. Crawford changed number to 42. |
| Apr 15 | Gabe Speier | Number Change | LHP Gabe Speier changed number to 42. |
| Apr 15 | Connor Joe | Number Change | 1B Connor Joe changed number to 42. |
| Apr 15 | Cal Raleigh | Number Change | C Cal Raleigh changed number to 42. |
| Apr 15 | Mitch Garver | Number Change | C Mitch Garver changed number to 42. |
| Apr 15 | Dominic Canzone | Number Change | RF Dominic Canzone changed number to 42. |
| Apr 15 | George Kirby | Number Change | RHP George Kirby changed number to 42. |
| Apr 15 | Julio Rodríguez | Number Change | CF Julio Rodríguez changed number to 42. |
| Apr 15 | Emerson Hancock | Number Change | RHP Emerson Hancock changed number to 42. |
| Apr 15 | Matt Brash | Number Change | RHP Matt Brash changed number to 42. |
| Apr 15 | Bryan Woo | Number Change | RHP Bryan Woo changed number to 42. |
| Apr 15 | Logan Gilbert | Number Change | RHP Logan Gilbert changed number to 42. |
| Apr 15 | Cooper Criswell | Number Change | RHP Cooper Criswell changed number to 42. |
| Apr 15 | Eduard Bazardo | Number Change | RHP Eduard Bazardo changed number to 42. |
| Apr 15 | Josh Naylor | Number Change | 1B Josh Naylor changed number to 42. |
| Apr 15 | Andrés Muñoz | Number Change | RHP Andrés Muñoz changed number to 42. |
| Apr 15 | José A. Ferrer | Number Change | LHP Jose A. Ferrer changed number to 42. |
| Apr 15 | Randy Arozarena | Number Change | LF Randy Arozarena changed number to 42. |
| Apr 15 | Leo Rivas | Number Change | 2B Leo Rivas changed number to 42. |
| Apr 15 | Rob Refsnyder | Number Change | RF Rob Refsnyder changed number to 42. |
| Apr 15 | Luke Raley | Number Change | RF Luke Raley changed number to 42. |
| Apr 14 | Patrick Wisdom | Selected | Seattle Mariners selected the contract of 1B Patrick Wisdom from Tacoma Rainiers. |
| Apr 14 | Rob Refsnyder | Status Change | Seattle Mariners placed RF Rob Refsnyder on the paternity list. |
| Apr 14 | Blas Castaño | Designated for Assignment | Seattle Mariners designated RHP Blas Castaño for assignment. |
| Apr 8 | Carlos Vargas | Status Change | Seattle Mariners transferred RHP Carlos Vargas from the 15-day injured list to the 60-day injured list. Right lat strain. |
| Apr 8 | Miles Mastrobuoni | Assigned | Seattle Mariners sent 3B Miles Mastrobuoni on a rehab assignment to Tacoma Rainiers. |
| Apr 8 | Victor Robles | Status Change | Seattle Mariners placed RF Victor Robles on the 10-day injured list retroactive to April 7, 2026. Right pec strain. |
| Apr 8 | Connor Joe | Selected | Seattle Mariners selected the contract of RF Connor Joe from Tacoma Rainiers. |
| Apr 7 | Ryan Loutos | Signed as Free Agent | Seattle Mariners signed free agent RHP Ryan Loutos to a minor league contract. |
| Apr 2 | Ryan Loutos | Released | Seattle Mariners released RHP Ryan Loutos. |
| Apr 2 | Ryan Bliss | Optioned | Seattle Mariners optioned 2B Ryan Bliss to Tacoma Rainiers. |
| Apr 2 | J.P. Crawford | Status Change | Seattle Mariners activated SS J.P. Crawford from the 10-day injured list. |
| Apr 1 | Colt Emerson | Optioned | Seattle Mariners optioned SS Colt Emerson to Tacoma Rainiers. |
| Mar 31 | J.P. Crawford | Assigned | Seattle Mariners sent SS J.P. Crawford on a rehab assignment to Tacoma Rainiers. |
| Mar 31 | Colt Emerson | Selected | Seattle Mariners selected the contract of SS Colt Emerson from Tacoma Rainiers. |
| Mar 31 | Ryan Loutos | Designated for Assignment | Seattle Mariners designated RHP Ryan Loutos for assignment. |
| Mar 31 | J.P. Crawford | Assigned | Seattle Mariners sent SS J.P. Crawford on a rehab assignment to Tacoma Rainiers. |
| Mar 27 | Adam Maier | Status Change | RHP Adam Maier roster status changed by Seattle Mariners. |
| Mar 27 | Chase Centala | Signed as Free Agent | Seattle Mariners signed free agent RHP Chase Centala to a minor league contract. |
| Mar 27 | Cole Wilcox | Recalled | Seattle Mariners recalled RHP Cole Wilcox from Tacoma Rainiers. |
| Mar 27 | Carlos Vargas | Status Change | Seattle Mariners placed RHP Carlos Vargas on the 15-day injured list retroactive to March 24, 2026. Right lat strain. |
| Mar 26 | Adam Maier | Signed as Free Agent | Seattle Mariners signed free agent RHP Adam Maier to a minor league contract. |
| Mar 26 | Cooper Criswell | Number Change | RHP Cooper Criswell changed number to 88. |
| Mar 25 | Andrew Knizner | Released | Seattle Mariners released C Andrew Knizner. |
| Mar 25 | Bryce Miller | Status Change | Seattle Mariners placed RHP Bryce Miller on the 15-day injured list retroactive to March 22, 2026. Left oblique strain. |
| Mar 25 | Miles Mastrobuoni | Status Change | Seattle Mariners placed 3B Miles Mastrobuoni on the 10-day injured list retroactive to March 22, 2026. Right calf strain. |
| Mar 25 | J.P. Crawford | Status Change | Seattle Mariners placed SS J.P. Crawford on the 10-day injured list retroactive to March 22, 2026. Right shoulder inflammation. |
| Mar 25 | Mitch Garver | Selected | Seattle Mariners selected the contract of C Mitch Garver from Tacoma Rainiers. |
| Mar 25 | Alex Hoppe | Optioned | Seattle Mariners optioned RHP Alex Hoppe to Tacoma Rainiers. |
| Mar 24 | Carlos Vargas | Status Change | Seattle Mariners placed RHP Carlos Vargas on the 15-day injured list. Right lat strain. |
| Mar 24 | Carlos Vargas | Status Change | Seattle Mariners transferred RHP Carlos Vargas from the 15-day injured list to the 60-day injured list. |
| Mar 24 | Will Armbruester | Signed as Free Agent | Seattle Mariners signed free agent RHP Will Armbruester to a minor league contract. |
| Mar 24 | Andrew Knizner | Designated for Assignment | Seattle Mariners designated C Andrew Knizner for assignment. |
| Mar 23 | Leandro Romero | Assigned | SS Leandro Romero assigned to Seattle Mariners. |
| Mar 23 | Brady O'Brien | Assigned | 2B Brady O'Brien assigned to Seattle Mariners. |
| Mar 23 | Casey Hintz | Assigned | RHP Casey Hintz assigned to Seattle Mariners. |
| Mar 22 | Jhonny Pereda | Optioned | Seattle Mariners optioned C Jhonny Pereda to Tacoma Rainiers. |
| Mar 22 | Cole Wilcox | Optioned | Seattle Mariners optioned RHP Cole Wilcox to Tacoma Rainiers. |
| Mar 22 | Yosver Zulueta | Optioned | Seattle Mariners optioned RHP Yosver Zulueta to Tacoma Rainiers. |
| Mar 22 | Cesar Quintas | Assigned | CF Cesar Quintas assigned to Seattle Mariners. |
| Mar 22 | Ricardo Cova | Assigned | 2B Ricardo Cova assigned to Seattle Mariners. |
| Mar 21 | Rhylan Thomas | Optioned | Seattle Mariners optioned LF Rhylan Thomas to Tacoma Rainiers. |
| Mar 20 | Guillo Zuñiga | Released | Seattle Mariners released RHP Guillo Zuñiga. |
| Mar 19 | Jose Geraldo | Assigned | RHP Jose Geraldo assigned to Seattle Mariners. |
| Mar 17 | Brayden Corn | Assigned | OF Brayden Corn assigned to Seattle Mariners. |
| Mar 17 | George Feliz | Assigned | CF George Feliz assigned to Seattle Mariners. |
| Mar 17 | Gunner Mayer | Assigned | RHP Gunner Mayer assigned to Seattle Mariners. |
| Mar 15 | Konni Durschlag | Assigned | OF Konni Durschlag assigned to Seattle Mariners. |
| Mar 14 | Robinson Ortiz | Optioned | Seattle Mariners optioned LHP Robinson Ortiz to Tacoma Rainiers. |
| Mar 14 | Wyatt Lunsford-Shenkman | Assigned | RHP Wyatt Lunsford-Shenkman assigned to Seattle Mariners. |
| Mar 14 | Ryan Picollo | Assigned | OF Ryan Picollo assigned to Seattle Mariners. |
| Mar 13 | Josh Simpson | Optioned | Seattle Mariners optioned LHP Josh Simpson to Tacoma Rainiers. |
| Mar 13 | Troy Taylor | Optioned | Seattle Mariners optioned RHP Troy Taylor to Tacoma Rainiers. |
| Mar 13 | Anthony Donofrio | Assigned | OF Anthony Donofrio assigned to Seattle Mariners. |
| Mar 13 | Jacob Denner | Assigned | LHP Jacob Denner assigned to Seattle Mariners. |
| Mar 12 | Aiden Taurek | Assigned | OF Aiden Taurek assigned to Seattle Mariners. |
| Mar 11 | Blas Castaño | Optioned | Seattle Mariners optioned RHP Blas Castaño to Tacoma Rainiers. |
| Mar 11 | Domingo Gonzalez | Optioned | Seattle Mariners optioned RHP Domingo Gonzalez to Tacoma Rainiers. |
| Mar 11 | Curtis Washington Jr. | Assigned | CF Curtis Washington Jr. assigned to Seattle Mariners. |
| Mar 10 | Carter Dorighi | Assigned | SS Carter Dorighi assigned to Seattle Mariners. |
| Mar 8 | Ryan Loutos | Optioned | Seattle Mariners optioned RHP Ryan Loutos to Tacoma Rainiers. |
| Mar 7 | Josh Hood | Assigned | 2B Josh Hood assigned to Seattle Mariners. |
| Mar 7 | Alejo Lopez | Assigned | 2B Alejo Lopez assigned to Seattle Mariners. |
| Mar 7 | Grant Jay | Assigned | C Grant Jay assigned to Seattle Mariners. |
| Mar 6 | Korbyn Dickerson | Assigned | OF Korbyn Dickerson assigned to Seattle Mariners. |
| Mar 6 | Matthew Ellis | Assigned | C Matthew Ellis assigned to Seattle Mariners. |
| Mar 5 | Colin Davis | Assigned | LF Colin Davis assigned to Seattle Mariners. |
| Mar 5 | Axel Sanchez | Assigned | SS Axel Sanchez assigned to Seattle Mariners. |
| Mar 5 | Aaron McKeithan | Assigned | C Aaron McKeithan assigned to Seattle Mariners. |
| Mar 4 | Hogan Windish | Assigned | 1B Hogan Windish assigned to Seattle Mariners. |
| Mar 3 | Connor Dykstra | Assigned | C Connor Dykstra assigned to Seattle Mariners. |
| Mar 3 | Mitch Garver | Assigned | C Mitch Garver assigned to Seattle Mariners. |
| Mar 1 | Bill Knight | Status Change | OF Bill Knight roster status changed by Seattle Mariners. |
| Mar 1 | Jacob Nottingham | Signed as Free Agent | Seattle Mariners signed free agent C Jacob Nottingham to a minor league contract. |
| Mar 1 | Bill Knight | Assigned | OF Bill Knight assigned to Seattle Mariners. |
| Feb 28 | Houston Roth | Assigned | RHP Houston Roth assigned to Seattle Mariners. |
| Feb 27 | Gabriel Sosa | Signed as Free Agent | Seattle Mariners signed free agent RHP Gabriel Sosa to a minor league contract. |
| Feb 26 | Mitch Garver | Signed as Free Agent | Seattle Mariners signed free agent C Mitch Garver to a minor league contract. |
| Feb 26 | Abdiel Mendoza | Assigned | RHP Abdiel Mendoza assigned to Seattle Mariners. |
| Feb 25 | Reid VanScoter | Assigned | LHP Reid VanScoter assigned to Seattle Mariners. |
| Feb 25 | Caleb Cali | Assigned | 3B Caleb Cali assigned to Seattle Mariners. |
| Feb 24 | Reid Easterly | Assigned | LHP Reid Easterly assigned to Seattle Mariners. |
| Feb 23 | Reese Lumpkin | Status Change | RHP Reese Lumpkin roster status changed by Seattle Mariners. |
| Feb 23 | Reese Lumpkin | Assigned | RHP Reese Lumpkin assigned to Seattle Mariners. |
| Feb 23 | Evan Truitt | Assigned | RHP Evan Truitt assigned to Seattle Mariners. |
| Feb 23 | Brandon Eike | Assigned | 3B Brandon Eike assigned to Seattle Mariners. |
| Feb 23 | Austin St. Laurent | Assigned | 3B Austin St. Laurent assigned to Seattle Mariners. |
| Feb 22 | Luis Suisbel | Status Change | 1B Luis Suisbel roster status changed by Seattle Mariners. |
| Feb 22 | Luis Suisbel | Status Change | 1B Luis Suisbel roster status changed by Seattle Mariners. |
| Feb 22 | Charlie Pagliarini | Status Change | 3B Charlie Pagliarini roster status changed by Seattle Mariners. |
| Feb 22 | Nick Garcia | Status Change | RHP Nick Garcia roster status changed by Seattle Mariners. |
| Feb 22 | Felnin Celesten | Status Change | SS Felnin Celesten roster status changed by Seattle Mariners. |
| Feb 22 | Nick Garcia | Signed as Free Agent | Seattle Mariners signed free agent RHP Nick Garcia to a minor league contract. |
| Feb 22 | Luis Suisbel | Assigned | 1B Luis Suisbel assigned to Seattle Mariners. |
| Feb 22 | Charlie Pagliarini | Assigned | 3B Charlie Pagliarini assigned to Seattle Mariners. |
| Feb 22 | Felnin Celesten | Assigned | SS Felnin Celesten assigned to Seattle Mariners. |
| Feb 22 | Jean Munoz | Assigned | RHP Jean Munoz assigned to Seattle Mariners. |
| Feb 22 | Marcelo Perez | Assigned | RHP Marcelo Perez assigned to Seattle Mariners. |
| Feb 21 | Alejo Lopez | Signed as Free Agent | Seattle Mariners signed free agent 2B Alejo Lopez to a minor league contract. |
| Feb 21 | Brendan White | Status Change | RHP Brendan White roster status changed by Seattle Mariners. |
| Feb 21 | Brendan White | Signed as Free Agent | Seattle Mariners signed free agent RHP Brendan White to a minor league contract. |
| Feb 21 | Ryan Hawks | Assigned | RHP Ryan Hawks assigned to Seattle Mariners. |
| Feb 21 | Ryan Hawks | Assigned | RHP Ryan Hawks assigned to Seattle Mariners. |
| Feb 21 | Nico Tellache | Assigned | LHP Nico Tellache assigned to Seattle Mariners. |
| Feb 21 | Stefan Raeth | Assigned | RHP Stefan Raeth assigned to Seattle Mariners. |
| Feb 21 | Aneury Lora | Assigned | RHP Aneury Lora assigned to Seattle Mariners. |
| Feb 20 | Jason Ruffcorn | Status Change | RHP Jason Ruffcorn roster status changed by Seattle Mariners. |
| Feb 20 | Dylan Wilson | Assigned | RHP Dylan Wilson assigned to Seattle Mariners. |
| Feb 20 | Jason Ruffcorn | Assigned | RHP Jason Ruffcorn assigned to Seattle Mariners. |
| Feb 20 | Jimmy Kingsbury | Assigned | RHP Jimmy Kingsbury assigned to Seattle Mariners. |
| Feb 20 | Peyton Alford | Assigned | LHP Peyton Alford assigned to Seattle Mariners. |
| Feb 19 | Santiago Pereira | Assigned | C Santiago Pereira assigned to Seattle Mariners. |
| Feb 16 | Logan Evans | Status Change | Seattle Mariners placed RHP Logan Evans on the 60-day injured list. Recovery from torn UCL in right arm. |
| Feb 16 | Josh Simpson | Trade | Miami Marlins traded LHP Josh Simpson to Seattle Mariners for cash. |
| Feb 13 | German Arvayo | Signed as Free Agent | Seattle Mariners signed free agent RHP German Arvayo to a minor league contract. |
| Feb 13 | Carlos Martinez | Signed as Free Agent | Seattle Mariners signed free agent RHP Carlos Martinez to a minor league contract. |
| Feb 13 | Houston Roth | Signed as Free Agent | Seattle Mariners signed free agent RHP Houston Roth to a minor league contract. |
| Feb 13 | Connor Joe | Signed as Free Agent | Seattle Mariners signed free agent RF Connor Joe to a minor league contract. |
| Feb 13 | Cristian Alvarado | Signed as Free Agent | Seattle Mariners signed free agent RHP Cristian Alvarado to a minor league contract. |
| Feb 13 | Adan Vallenilla | Signed as Free Agent | Seattle Mariners signed free agent RHP Adan Vallenilla to a minor league contract. |
| Feb 13 | Edgardo Toro | Signed as Free Agent | Seattle Mariners signed free agent OF Edgardo Toro to a minor league contract. |
| Feb 13 | Gabriel Hidalgo | Signed as Free Agent | Seattle Mariners signed free agent RHP Gabriel Hidalgo to a minor league contract. |
| Feb 13 | Fabian Gonzalez | Signed as Free Agent | Seattle Mariners signed free agent IF Fabian Gonzalez to a minor league contract. |
| Feb 13 | Daniel Alana | Signed as Free Agent | Seattle Mariners signed free agent C Daniel Alana to a minor league contract. |
| Feb 12 | Jhonathan Díaz | Status Change | LHP Jhonathan Díaz roster status changed by Seattle Mariners. |
| Feb 12 | Jhonathan Díaz | Assigned | Seattle Mariners invited non-roster LHP Jhonathan Díaz to spring training. |
| Feb 10 | Daniel Amaral | Signed as Free Agent | Seattle Mariners signed free agent OF Daniel Amaral to a minor league contract. |
| Feb 9 | Jhonathan Díaz | Status Change | LHP Jhonathan Díaz roster status changed by Seattle Mariners. |
| Feb 9 | Jhonathan Díaz | Signed as Free Agent | Seattle Mariners signed free agent LHP Jhonathan Díaz. |
| Feb 5 | Ben Hernandez | Signed as Free Agent | Seattle Mariners signed free agent RHP Ben Hernandez to a minor league contract. |
| Feb 3 | Ray Cebulski | Signed as Free Agent | Seattle Mariners signed free agent RHP Ray Cebulski to a minor league contract. |
| Feb 3 | Robert Emery | Signed as Free Agent | Seattle Mariners signed free agent C Robert Emery to a minor league contract. |
| Feb 3 | Jackson Kowar | Claimed Off Waivers | Minnesota Twins claimed RHP Jackson Kowar off waivers from Seattle Mariners. |
| Feb 2 | Ben Williamson | Trade | St. Louis Cardinals traded 2B Brendan Donovan to Seattle Mariners for CF Colton Ledbetter, SHP Jurrangelo Cijntje, OF Tai Peete, Draft Pick and Draft Pick. |
| Jan 30 | Josh Caron | Status Change | C Josh Caron roster status changed by Seattle Mariners. |
| Jan 30 | Nick Davila | Status Change | RHP Nick Davila roster status changed by Seattle Mariners. |
| Jan 30 | Jared Sundstrom | Assigned | Seattle Mariners invited non-roster OF Jared Sundstrom to spring training. |
| Jan 30 | Luke Stevenson | Assigned | Seattle Mariners invited non-roster C Luke Stevenson to spring training. |
| Jan 30 | Brock Rodden | Assigned | Seattle Mariners invited non-roster 2B Brock Rodden to spring training. |
| Jan 30 | Nick Raposo | Assigned | Seattle Mariners invited non-roster C Nick Raposo to spring training. |
| Jan 30 | Blake Rambusch | Assigned | Seattle Mariners invited non-roster OF Blake Rambusch to spring training. |
| Jan 30 | Spencer Packard | Assigned | Seattle Mariners invited non-roster OF Spencer Packard to spring training. |
| Jan 30 | Brian O'Keefe | Signed as Free Agent | Seattle Mariners signed free agent C Brian O'Keefe to a minor league contract and invited him to spring training. |
| Jan 30 | Lazaro Montes | Assigned | Seattle Mariners invited non-roster RF Lazaro Montes to spring training. |
| Jan 30 | Victor Labrada | Assigned | Seattle Mariners invited non-roster CF Victor Labrada to spring training. |
| Jan 30 | Colt Emerson | Assigned | Seattle Mariners invited non-roster SS Colt Emerson to spring training. |
| Jan 30 | Jonny Farmelo | Assigned | Seattle Mariners invited non-roster OF Jonny Farmelo to spring training. |
| Jan 30 | Connor Charping | Assigned | Seattle Mariners invited non-roster C Connor Charping to spring training. |
| Jan 30 | Josh Caron | Assigned | Seattle Mariners invited non-roster C Josh Caron to spring training. |
| Jan 30 | Michael Arroyo | Assigned | Seattle Mariners invited non-roster SS Michael Arroyo to spring training. |
| Jan 30 | Guillo Zuñiga | Assigned | Seattle Mariners invited non-roster RHP Guillo Zuñiga to spring training. |
| Jan 30 | Ryan Sloan | Assigned | Seattle Mariners invited non-roster RHP Ryan Sloan to spring training. |
| Jan 30 | Michael Morales | Assigned | Seattle Mariners invited non-roster RHP Michael Morales to spring training. |
| Jan 30 | Teddy McGraw | Assigned | Seattle Mariners invited non-roster RHP Teddy McGraw to spring training. |
| Jan 30 | Austin Kitchen | Assigned | Seattle Mariners invited non-roster LHP Austin Kitchen to spring training. |
| Jan 30 | Nick Davila | Assigned | Seattle Mariners invited non-roster RHP Nick Davila to spring training. |
| Jan 30 | Tyler Cleveland | Assigned | Seattle Mariners invited non-roster RHP Tyler Cleveland to spring training. |
| Jan 30 | Jurrangelo Cijntje | Assigned | Seattle Mariners invited non-roster SHP Jurrangelo Cijntje to spring training. |
| Jan 30 | Charlie Beilenson | Assigned | Seattle Mariners invited non-roster RHP Charlie Beilenson to spring training. |
| Jan 30 | Kade Anderson | Assigned | Seattle Mariners invited non-roster LHP Kade Anderson to spring training. |
| Jan 28 | Jhonathan Díaz | Outrighted | Seattle Mariners sent LHP Jhonathan Díaz outright to Tacoma Rainiers. |
| Jan 27 | Gunner Mayer | Signed as Free Agent | Seattle Mariners signed free agent RHP Gunner Mayer to a minor league contract. |
| Jan 27 | — | Trade | Minnesota Twins traded C Jhonny Pereda to Seattle Mariners for cash. |
| Jan 27 | Jackson Kowar | Designated for Assignment | Seattle Mariners designated RHP Jackson Kowar for assignment. |
| Jan 26 | Will Wilson | Status Change | 3B Will Wilson roster status changed by Seattle Mariners. |
| Jan 26 | Will Wilson | Signed as Free Agent | Seattle Mariners signed free agent 3B Will Wilson to a minor league contract. |
| Jan 26 | Abdiel Mendoza | Signed as Free Agent | Seattle Mariners signed free agent RHP Abdiel Mendoza to a minor league contract. |
| Jan 26 | Aaron McKeithan | Signed as Free Agent | Seattle Mariners signed free agent C Aaron McKeithan to a minor league contract. |
| Jan 24 | Jakson Reetz | Status Change | C Jakson Reetz roster status changed by Seattle Mariners. |
| Jan 24 | Jakson Reetz | Signed as Free Agent | Seattle Mariners signed free agent C Jakson Reetz to a minor league contract. |
| Jan 23 | Jhonathan Díaz | Designated for Assignment | Seattle Mariners designated LHP Jhonathan Díaz for assignment. |
| Jan 23 | — | Trade | New York Mets traded RHP Cooper Criswell to Seattle Mariners for cash. |
| Jan 22 | Dane Dunning | Status Change | RHP Dane Dunning roster status changed by Seattle Mariners. |
| Jan 22 | Dane Dunning | Signed as Free Agent | Seattle Mariners signed free agent RHP Dane Dunning to a minor league contract. |
| Jan 22 | Samad Taylor | Outrighted | Seattle Mariners sent 2B Samad Taylor outright to Tacoma Rainiers. |
| Jan 21 | Jack Bowery | Signed as Free Agent | Seattle Mariners signed free agent LHP Jack Bowery to a minor league contract. |
| Jan 20 | Patrick Wisdom | Status Change | 1B Patrick Wisdom roster status changed by Seattle Mariners. |
| Jan 20 | Patrick Wisdom | Signed as Free Agent | Seattle Mariners signed free agent 1B Patrick Wisdom to a minor league contract. |
| Jan 16 | Gabe Mosser | Status Change | RHP Gabe Mosser roster status changed by Seattle Mariners. |
| Jan 16 | Gabe Mosser | Signed as Free Agent | Seattle Mariners signed free agent RHP Gabe Mosser to a minor league contract. |
| Jan 15 | Ambeiro Recio | Signed as Free Agent | Seattle Mariners signed free agent OF Ambeiro Recio to a minor league contract. |
| Jan 15 | Leonardo Reynoso | Signed as Free Agent | Seattle Mariners signed free agent SS Leonardo Reynoso to a minor league contract. |
| Jan 15 | Jarvis Gomez | Signed as Free Agent | Seattle Mariners signed free agent OF Jarvis Gomez to a minor league contract. |
| Jan 15 | Gregory Pio | Signed as Free Agent | Seattle Mariners signed free agent OF Gregory Pio to a minor league contract. |
| Jan 15 | Juan Rijo | Signed as Free Agent | Seattle Mariners signed free agent OF Juan Rijo to a minor league contract. |
| Jan 15 | Yosver Zulueta | Trade | Cincinnati Reds traded RHP Yosver Zulueta to Seattle Mariners for RHP Dusty Revis. |
| Jan 15 | Samad Taylor | Designated for Assignment | Seattle Mariners designated 2B Samad Taylor for assignment. |
| Jan 12 | J.T. Arruda | Status Change | 2B J.T. Arruda roster status changed by Seattle Mariners. |
| Jan 12 | J.T. Arruda | Signed as Free Agent | Seattle Mariners signed free agent SS J.T. Arruda to a minor league contract. |
| Jan 8 | Michael Rucker | Status Change | RHP Michael Rucker roster status changed by Seattle Mariners. |
| Jan 8 | Michael Rucker | Signed as Free Agent | Seattle Mariners signed free agent RHP Michael Rucker to a minor league contract. |
| Jan 4 | Logan Evans | Number Change | RHP Logan Evans changed number to 23. |