Mariners Roster & Staff
Transactions
| Date | Transaction |
| 05/31/17 | Seattle Mariners activated LHP James Paxton from the 10-day disabled list. |
| 05/31/17 | Seattle Mariners optioned RHP Ryne Harper to Tacoma Rainiers. |
| 05/28/17 | Seattle Mariners optioned RHP Rob Whalen to Tacoma Rainiers. |
| 05/28/17 | Seattle Mariners selected the contract of Ryne Harper from Tacoma Rainiers. |
| 05/26/17 | Los Angeles Dodgers claimed RHP Chris Heston off waivers from Seattle Mariners. |
| 05/26/17 | Los Angeles Dodgers claimed 2B Mike Freeman off waivers from Seattle Mariners. |
| 05/26/17 | Seattle Mariners sent LHP James Paxton on a rehab assignment to Arkansas Travelers. |
| 05/25/17 | Seattle Mariners signed free agent RHP Melquiades Escobar to a minor league contract. |
| 05/24/17 | Seattle Mariners designated RHP Chris Heston for assignment. |
| 05/24/17 | Seattle Mariners signed free agent LF Jeff Kobernus to a minor league contract. |
| 05/24/17 | Houston Astros traded CF Andrew Aplin to Seattle Mariners for Player To Be Named Later. |
| 05/24/17 | Seattle Mariners optioned CF Andrew Aplin to Tacoma Rainiers. |
| 05/24/17 | Seattle Mariners recalled Rob Whalen from Tacoma Rainiers. |
| 05/24/17 | Seattle Mariners optioned RHP Emilio Pagan to Tacoma Rainiers. |
| 05/23/17 | Seattle Mariners activated 2B Robinson Cano from the 10-day disabled list. |
| 05/22/17 | Seattle Mariners recalled Emilio Pagan from Tacoma Rainiers. |
| 05/22/17 | Seattle Mariners optioned 1B Daniel Vogelbach to Tacoma Rainiers. |
| 05/22/17 | Seattle Mariners recalled C Mike Zunino from Tacoma Rainiers. |
| 05/22/17 | Seattle Mariners optioned C Tuffy Gosewisch to Tacoma Rainiers. |
| 05/22/17 | Seattle Mariners optioned RHP Chris Heston to Tacoma Rainiers. |
| 05/21/17 | Seattle Mariners recalled Daniel Vogelbach from Tacoma Rainiers. |
| 05/21/17 | Seattle Mariners optioned LHP Dillon Overton to Tacoma Rainiers. |
| 05/21/17 | Seattle Mariners optioned 2B Mike Freeman to Tacoma Rainiers. |
| 05/21/17 | Seattle Mariners recalled Chris Heston from Tacoma Rainiers. |
| 05/21/17 | Seattle Mariners signed free agent LF Keury De La Cruz to a minor league contract. |
| 05/19/17 | Seattle Mariners signed free agent RHP Fabian Roman to a minor league contract. |
| 05/18/17 | Seattle Mariners signed RHP Ryan Kelly. |
| 05/17/17 | Seattle Mariners optioned RHP Chase De Jong to Tacoma Rainiers. |
| 05/17/17 | Seattle Mariners recalled Casey Lawrence from Tacoma Rainiers. |
| 05/16/17 | Seattle Mariners placed 2B Robinson Cano on the 10-day disabled list retroactive to May 13, 2017. Right quad strain. |
| 05/16/17 | Seattle Mariners recalled Boog Powell from Tacoma Rainiers. |
| 05/15/17 | Seattle Mariners optioned LHP Zac Curtis to Arkansas Travelers. |
| 05/15/17 | Seattle Mariners activated RHP Steve Cishek from the 10-day disabled list. |
| 05/14/17 | Seattle Mariners recalled Dan Altavilla from Tacoma Rainiers. |
| 05/14/17 | Seattle Mariners sent RHP Jean Machi outright to Tacoma Rainiers. |
| 05/14/17 | Seattle Mariners placed RHP Ryan Weber on the 10-day disabled list. Right biceps strain. |
| 05/13/17 | Seattle Mariners selected the contract of RHP Ryan Weber from Tacoma Rainiers. |
| 05/13/17 | Seattle Mariners designated Jean Machi for assignment. |
| 05/13/17 | Seattle Mariners signed free agent RHP Austin Kubitza to a minor league contract. |
| 05/12/17 | Seattle Mariners signed free agent RHP Tyler Cloyd to a minor league contract. |
| 05/11/17 | Seattle Mariners transferred RHP Evan Scribner from the 10-day disabled list to the 60-day disabled list. Flexor bundle strain. |
| 05/11/17 | Seattle Mariners signed free agent 3B Danny Muno to a minor league contract. |
| 05/11/17 | Seattle Mariners optioned RHP Casey Lawrence to Tacoma Rainiers. |
| 05/11/17 | Seattle Mariners claimed RHP Casey Lawrence off waivers from Toronto Blue Jays. |
| 05/11/17 | Seattle Mariners recalled Zac Curtis from Arkansas Travelers. |
| 05/11/17 | Seattle Mariners optioned RHP Dan Altavilla to Tacoma Rainiers. |
| 05/11/17 | Seattle Mariners sent RHP Steve Cishek on a rehab assignment to Tacoma Rainiers. |
| 05/11/17 | Seattle Mariners signed free agent RHP Justin DeFratus to a minor league contract. |
| 05/10/17 | Seattle Mariners transferred RHP Evan Marshall from the 10-day disabled list to the 60-day disabled list. Strained right hamstring. |
| 05/10/17 | Seattle Mariners signed free agent LHP Tyler Watson to a minor league contract. |
| 05/10/17 | Seattle Mariners placed RHP Hisashi Iwakuma on the 10-day disabled list retroactive to May 7, 2017. Inflammation in right shoulder. |
| 05/10/17 | Seattle Mariners selected the contract of Sam Gaviglio from Tacoma Rainiers. |
| 05/09/17 | Seattle Mariners traded RHP Casey Fien to Philadelphia Phillies for cash. |
| 05/09/17 | Tampa Bay Rays traded RHP Bryan Bonnell to Seattle Mariners for Future Considerations. |
| 05/08/17 | Seattle Mariners signed free agent RHP Christian Pedrol to a minor league contract. |
| 05/07/17 | Seattle Mariners optioned RHP Rob Whalen to Tacoma Rainiers. |
| 05/07/17 | Seattle Mariners transferred RHP Shae Simmons from the 10-day disabled list to the 60-day disabled list. Right elbow strain. |
| 05/07/17 | Seattle Mariners selected the contract of Christian Bergman from Tacoma Rainiers. |
| 05/06/17 | Seattle Mariners recalled Dan Altavilla from Tacoma Rainiers. |
| 05/06/17 | Seattle Mariners placed RHP Evan Marshall on the 10-day disabled list. Strained right hamstring. |
| 05/06/17 | Seattle Mariners recalled Rob Whalen from Tacoma Rainiers. |
| 05/06/17 | Seattle Mariners optioned RHP Emilio Pagan to Tacoma Rainiers. |
| 05/05/17 | Seattle Mariners recalled RHP Evan Marshall from Tacoma Rainiers. |
| 05/05/17 | Seattle Mariners optioned C Mike Zunino to Tacoma Rainiers. |
| 05/05/17 | Seattle Mariners recalled Tuffy Gosewisch from Tacoma Rainiers. |
| 05/05/17 | Seattle Mariners optioned CF Boog Powell to Tacoma Rainiers. |
| 05/05/17 | Seattle Mariners placed LHP James Paxton on the 10-day disabled list retroactive to May 3, 2017. Left forearm strain. |
| 05/05/17 | Seattle Mariners recalled Mike Freeman from Tacoma Rainiers. |
| 05/03/17 | Seattle Mariners sent RHP Casey Fien outright to Tacoma Rainiers. |
| 05/02/17 | Seattle Mariners optioned 1B Daniel Vogelbach to Tacoma Rainiers. |
| 05/02/17 | Seattle Mariners selected the contract of RHP Jean Machi from Tacoma Rainiers. |
| 05/02/17 | Shawn O'Malley roster status changed by Seattle Mariners. |
| 05/02/17 | Seattle Mariners designated Casey Fien for assignment. |
| 05/02/17 | Seattle Mariners selected the contract of Emilio Pagan from Tacoma Rainiers. |