Mariners Roster & Staff
Transactions
| Date | Transaction |
| 05/04/26 | Seattle Mariners placed LHP Gabe Speier on the 15-day injured list retroactive to May 3, 2026. Left shoulder inflammation. |
| 05/04/26 | Seattle Mariners activated LHP José Suarez. |
| 05/04/26 | Seattle Mariners optioned RHP Cole Wilcox to Tacoma Rainiers. |
| 05/04/26 | Seattle Mariners recalled LHP Josh Simpson from Tacoma Rainiers. |
| 05/03/26 | Seattle Mariners designated LF Rhylan Thomas for assignment. |
| 05/03/26 | Seattle Mariners sent RF Victor Robles on a rehab assignment to Tacoma Rainiers. |
| 05/03/26 | Seattle Mariners claimed LHP José Suarez off waivers from Atlanta Braves. |
| 05/02/26 | Seattle Mariners placed 3B Will Wilson on the 10-day injured list retroactive to April 30, 2026. Left thumb fracture. |
| 05/02/26 | Seattle Mariners optioned LHP Josh Simpson to Tacoma Rainiers. |
| 05/02/26 | Seattle Mariners selected the contract of RHP Nick Davila from Arkansas Travelers. |
| 05/02/26 | Seattle Mariners recalled C Jhonny Pereda from Tacoma Rainiers. |
| 05/01/26 | Seattle Mariners placed RHP Matt Brash on the 15-day injured list retroactive to April 30, 2026. Right lat inflammation. |
| 05/01/26 | Seattle Mariners purchased contract of RHP Adam Smith. |
| 05/01/26 | Seattle Mariners recalled LHP Josh Simpson from Tacoma Rainiers. |