Mariners Roster & Staff
Transactions
| Date | Transaction |
| 12/26/12 | Seattle Mariners signed free agent LF Raul Ibanez. |
| 12/26/12 | Seattle Mariners designated D.J. Mitchell for assignment. |
| 12/21/12 | Seattle Mariners signed free agent RHP Jeremy Bonderman to a minor league contract and invited him to spring training. |
| 12/20/12 | Seattle Mariners signed free agent 1B Mike Jacobs to a minor league contract and invited him to spring training. |
| 12/19/12 | Los Angeles Angels traded 1B Kendrys Morales to Seattle Mariners for LHP Jason Vargas. |
| 12/19/12 | Seattle Mariners signed free agent 3B Leury Bonilla to a minor league contract. |
| 12/19/12 | Los Angeles Angels traded 1B Kendrys Morales to Seattle Mariners for LHP Jason Vargas. |
| 12/16/12 | Seattle Mariners signed free agent SS Rayder Ascanio to a minor league contract. |
| 12/14/12 | Philadelphia Phillies claimed Mauricio Robles off waivers from Seattle Mariners. |
| 12/12/12 | Seattle Mariners signed free agent C Raymon Tenias to a minor league contract. |
| 12/08/12 | Seattle Mariners designated Mauricio Robles for assignment. |
| 12/08/12 | Seattle Mariners signed free agent RF Jason Bay. |
| 12/06/12 | Seattle Mariners signed free agent OF Luis Liberato to a minor league contract. |