Mariners Roster & Staff
Transactions
| Date | Transaction |
| 06/30/12 | Seattle Mariners signed free agent SS Erick Mejia to a minor league contract. |
| 06/29/12 | Seattle Mariners recalled Steve Delabar from Tacoma Rainiers. |
| 06/29/12 | Seattle Mariners placed CF Franklin Gutierrez on the 7-day disabled list. Concussion |
| 06/29/12 | Seattle Mariners signed free agent RHP Cameron Copping to a minor league contract. |
| 06/22/12 | OF Jose Guedez assigned to AZL Mariners from Seattle Mariners. |
| 06/21/12 | Seattle Mariners sent RF Chih-Hsien Chiang outright to Jackson Generals. |
| 06/20/12 | Isaiah Yates assigned to AZL Mariners from Seattle Mariners. |
| 06/20/12 | RHP Logan Seifrit assigned to AZL Mariners from Seattle Mariners. |
| 06/20/12 | Keith Werman assigned to AZL Mariners from Seattle Mariners. |
| 06/18/12 | Seattle Mariners signed OF Isaiah Yates. |
| 06/17/12 | Seattle Mariners signed free agent 2B Keith Werman to a minor league contract. |
| 06/16/12 | Seattle Mariners designated Chih-Hsien Chiang for assignment. |
| 06/16/12 | Seattle Mariners optioned Steve Delabar to Tacoma Rainiers. |
| 06/16/12 | Seattle Mariners selected the contract of LHP Oliver Perez from Tacoma Rainiers. |
| 06/15/12 | Seattle Mariners signed RHP Logan Seifrit. |
| 06/14/12 | Edwin Diaz assigned to AZL Mariners from Seattle Mariners. |
| 06/14/12 | Seattle Mariners signed RHP Edwin Diaz. |
| 06/14/12 | Seattle Mariners signed LHP Tyler Pike. |
| 06/14/12 | Tyler Pike assigned to AZL Mariners from Seattle Mariners. |
| 06/13/12 | Seattle Mariners signed SS Tim Lopes. |
| 06/13/12 | Seattle Mariners signed RHP Mark Bordonaro. |
| 06/13/12 | Seattle Mariners signed 2B Brock Hebert. |
| 06/13/12 | Seattle Mariners signed OF Dario Pizzano. |
| 06/13/12 | Seattle Mariners signed OF Jabari Henry. |
| 06/13/12 | Seattle Mariners signed LHP Nate Koneski. |
| 06/13/12 | Seattle Mariners signed RHP Levi Dean. |
| 06/13/12 | Seattle Mariners signed LHP Blake Holovach. |
| 06/13/12 | Seattle Mariners signed RHP Matt Brazis. |
| 06/13/12 | Seattle Mariners signed C Toby DeMello. |
| 06/13/12 | Seattle Mariners signed SS Joseph DeCarlo. |
| 06/13/12 | Seattle Mariners signed 1B Kristian Brito. |
| 06/13/12 | Seattle Mariners signed SS Gabrial Franca. |
| 06/13/12 | Seattle Mariners signed RHP Aaron Brooks. |
| 06/13/12 | Seattle Mariners signed LHP Rusty Shellhorn. |
| 06/13/12 | Seattle Mariners signed 2B Richard Palase. |
| 06/13/12 | Seattle Mariners signed SS Chris Taylor. |
| 06/13/12 | Seattle Mariners signed LHP Steven Ewing. |
| 06/13/12 | Seattle Mariners signed RHP Dominic Leone. |
| 06/13/12 | Seattle Mariners signed OF Michael Faulkner. |
| 06/13/12 | Seattle Mariners signed 2B Jamodrick McGruder. |
| 06/13/12 | Seattle Mariners signed 1B Taylor Ard. |
| 06/13/12 | Seattle Mariners signed 3B Patrick Kivlehan. |
| 06/13/12 | Seattle Mariners signed RHP Blake Hauser. |
| 06/13/12 | Seattle Mariners signed RHP Grady Wood. |
| 06/13/12 | Seattle Mariners signed RHP Matt Vedo. |
| 06/13/12 | Seattle Mariners signed LHP Scott DeCecco. |
| 06/13/12 | Seattle Mariners optioned Alex Liddi to Tacoma Rainiers. |
| 06/13/12 | Seattle Mariners optioned Blake Beavan to Tacoma Rainiers. |
| 06/13/12 | Seattle Mariners activated CF Franklin Gutierrez from the 15-day disabled list. |
| 06/13/12 | Stephen Pryor roster status changed by Seattle Mariners. |
| 06/13/12 | Seattle Mariners recalled RHP Erasmo Ramirez from Tacoma Rainiers. |
| 06/13/12 | Seattle Mariners recalled Casper Wells from Tacoma Rainiers. |
| 06/13/12 | Mike Carp roster status changed by Seattle Mariners. |
| 06/13/12 | Seattle Mariners recalled Steve Delabar from Tacoma Rainiers. |
| 06/01/12 | Seattle Mariners signed free agent SS Luis Caballero to a minor league contract. |
| 06/01/12 | Seattle Mariners signed free agent LHP Oliver Asencio to a minor league contract. |
| 06/01/12 | Seattle Mariners transferred LHP George Sherrill from the 15-day disabled list to the 60-day disabled list. |
| 06/01/12 | Seattle Mariners selected the contract of RHP Stephen Pryor from Tacoma Rainiers. |