Mariners Roster & Staff
Transactions
| Date | Transaction |
| 11/21/25 | RHP Trent Thornton elected free agency. |
| 11/21/25 | RHP Gregory Santos elected free agency. |
| 11/20/25 | LHP Tayler Saucedo elected free agency. |
| 11/19/25 | Seattle Mariners signed free agent RHP Jose Gabriel Torres to a minor league contract. |
| 11/18/25 | Seattle Mariners designated LHP Tayler Saucedo for assignment. |
| 11/18/25 | RHP Alex Hoppe roster status changed by Seattle Mariners. |
| 11/18/25 | Boston Red Sox traded RHP Alex Hoppe to Seattle Mariners for C Luke Heyman. |
| 11/18/25 | Boston Red Sox traded RHP Alex Hoppe to Seattle Mariners for C Luke Heyman. |
| 11/17/25 | Seattle Mariners signed free agent RHP Randy Dobnak to a minor league contract. |
| 11/17/25 | Seattle Mariners signed free agent 1B Josh Naylor. |
| 11/16/25 | Los Angeles Dodgers traded LHP Robinson Ortiz to Seattle Mariners for RHP Tyler Gough. |
| 11/16/25 | Los Angeles Dodgers traded LHP Robinson Ortiz to Seattle Mariners for RHP Tyler Gough. |
| 11/06/25 | Seattle Mariners claimed RHP Ryan Loutos off waivers from Washington Nationals. |
| 11/05/25 | Seattle Mariners activated RHP Trent Thornton from the 60-day injured list. |
| 11/05/25 | Seattle Mariners activated RHP Gregory Santos from the 60-day injured list. |
| 11/05/25 | Seattle Mariners activated 2B Ryan Bliss from the 60-day injured list. |
| 11/05/25 | 2B Jorge Polanco elected free agency. |
| 11/05/25 | Tampa Bay Rays traded RHP Cole Wilcox to Seattle Mariners for cash. |
| 11/03/25 | C Mitch Garver elected free agency. |
| 11/02/25 | 3B Eugenio Suárez elected free agency. |
| 11/02/25 | 1B Josh Naylor elected free agency. |
| 11/02/25 | LHP Caleb Ferguson elected free agency. |
| 11/02/25 | RHP Luke Jackson elected free agency. |