Mariners Roster & Staff
Transactions
| Date | Transaction |
| 07/31/26 | Seattle Mariners placed SS J.P. Crawford on the 10-day injured list retroactive to July 30, 2026. Left wrist inflammation. |
| 07/31/26 | Seattle Mariners recalled 3B Leo Rivas from Tacoma Rainiers. |
| 07/28/26 | Seattle Mariners designated 1B Buddy Kennedy for assignment. |
| 07/28/26 | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Tacoma Rainiers. |
| 07/28/26 | Seattle Mariners activated DH Rob Refsnyder from the 10-day injured list. |
| 07/27/26 | Seattle Mariners signed free agent RHP Similien Senatus to a minor league contract. |
| 07/26/26 | Seattle Mariners optioned RHP Nick Davila to Tacoma Rainiers. |
| 07/26/26 | Seattle Mariners recalled RHP Alex Hoppe from Tacoma Rainiers. |
| 07/21/26 | Seattle Mariners signed free agent C Jake Harvey to a minor league contract. |
| 07/21/26 | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Everett AquaSox. |
| 07/21/26 | Seattle Mariners signed 3B Ace Reese. |
| 07/21/26 | Seattle Mariners signed free agent OF Kyle Boylston to a minor league contract. |
| 07/21/26 | Seattle Mariners signed free agent C Jacob Galloway to a minor league contract. |
| 07/21/26 | Seattle Mariners signed free agent RHP Isaac Thornton to a minor league contract. |
| 07/21/26 | Seattle Mariners sent 3B Miles Mastrobuoni outright to Tacoma Rainiers. |
| 07/18/26 | Seattle Mariners activated CF Julio Rodríguez from the 7-day injured list. |
| 07/18/26 | Seattle Mariners sent DH Rob Refsnyder on a rehab assignment to Tacoma Rainiers. |
| 07/18/26 | Seattle Mariners designated 3B Miles Mastrobuoni for assignment. |
| 07/18/26 | Seattle Mariners sent DH Rob Refsnyder on a rehab assignment to Tacoma Rainiers. |
| 07/17/26 | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Tacoma Rainiers. |
| 07/17/26 | Seattle Mariners signed RHP Wyatt Queen. |
| 07/17/26 | Seattle Mariners signed RHP Connor Marshburn. |
| 07/17/26 | Seattle Mariners signed RHP Drew Whalen. |
| 07/17/26 | Seattle Mariners signed RHP Connor Marshburn. |
| 07/17/26 | Seattle Mariners signed OF Michael Petite. |
| 07/17/26 | Seattle Mariners signed OF Charlie Sutherland. |
| 07/17/26 | Seattle Mariners signed OF Hayden Yost. |
| 07/17/26 | Seattle Mariners signed 3B Henry Ford. |
| 07/17/26 | Seattle Mariners signed free agent SS Henry Kaczmar to a minor league contract. |
| 07/17/26 | Seattle Mariners signed C Mason Eckelman. |
| 07/17/26 | Seattle Mariners signed RHP Anthony Treto. |
| 07/17/26 | Seattle Mariners signed RHP Nathan Taylor. |
| 07/17/26 | Seattle Mariners signed RHP Matthew Matthijs. |
| 07/17/26 | Seattle Mariners signed 3B Trevor Lucas. |
| 07/17/26 | Seattle Mariners signed RHP Chris Diaz. |
| 07/17/26 | Seattle Mariners signed OF Jake Brown. |
| 07/17/26 | Seattle Mariners signed SS Ryan Wynn. |
| 07/17/26 | Seattle Mariners signed 2B Eric Jeon. |
| 07/17/26 | Seattle Mariners signed LHP Chris Torres. |
| 07/17/26 | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to Tacoma Rainiers. |
| 07/15/26 | Seattle Mariners sent 3B Brendan Donovan on a rehab assignment to ACL Mariners. |
| 07/11/26 | Seattle Mariners traded 1B Carson Taylor to Atlanta Braves. |
| 07/07/26 | Seattle Mariners signed free agent RHP Mario Vasquez to a minor league contract. |
| 07/07/26 | CF Stuart Fairchild assigned to ACL Mariners from Seattle Mariners. |
| 07/05/26 | Seattle Mariners signed free agent CF Stuart Fairchild to a minor league contract. |
| 07/05/26 | CF Stuart Fairchild roster status changed by Seattle Mariners. |
| 07/03/26 | Seattle Mariners transferred RHP Cooper Criswell from the 15-day injured list to the 60-day injured list. Right shoulder strain. |
| 07/03/26 | Seattle Mariners placed CF Julio Rodríguez on the 7-day injured list. Concussion. |
| 07/03/26 | Seattle Mariners selected the contract of 3B Miles Mastrobuoni from Tacoma Rainiers. |