Mariners Roster & Staff
Transactions
| Date | Transaction |
| 09/28/20 | Seattle Mariners activated C Luis Torrens from the 10 day injured list. |
| 09/28/20 | Seattle Mariners activated 1B Dylan Moore from the 7 day injured list. |
| 09/28/20 | Seattle Mariners activated C Luis Torrens from the 10-day injured list. |
| 09/28/20 | Seattle Mariners activated C Luis Torrens from the 10 day injured list. |
| 09/28/20 | Seattle Mariners activated 1B Dylan Moore from the 7-day injured list. |
| 09/28/20 | Seattle Mariners activated 1B Dylan Moore from the 7 day injured list. |
| 09/28/20 | Seattle Mariners activated 1B Dylan Moore from the 7 day injured list. |
| 09/28/20 | Seattle Mariners activated C Luis Torrens from the 10 day injured list. |
| 09/28/20 | Seattle Mariners recalled LHP Aaron Fletcher from Mariners Alternate Training Site. |
| 09/28/20 | Seattle Mariners activated CF Jake Fraley from the 10-day injured list. |
| 09/28/20 | Seattle Mariners activated 2B Shed Long Jr. from the 10-day injured list. |
| 09/28/20 | Seattle Mariners recalled RHP Art Warren from Mariners Alternate Training Site. |
| 09/28/20 | Seattle Mariners recalled RHP Seth Frankoff from Mariners Alternate Training Site. |
| 09/28/20 | Seattle Mariners activated C Luis Torrens from the 10-day injured list. |
| 09/28/20 | Seattle Mariners recalled RHP Ian Hamilton from Mariners Alternate Training Site. |
| 09/28/20 | Seattle Mariners activated 3B Dylan Moore from the 7-day injured list. |
| 09/28/20 | Seattle Mariners recalled 2B Donovan Walton from Mariners Alternate Training Site. |
| 09/28/20 | Seattle Mariners activated 2B Sam Haggerty from the 10-day injured list. |
| 09/28/20 | Seattle Mariners activated 1B Dylan Moore from the 7-day injured list. |
| 09/27/20 | Seattle Mariners recalled C Joe Hudson from Mariners Alternate Training Site. |
| 09/27/20 | Seattle Mariners placed C Luis Torrens on the 10-day injured list. Back spasms. |
| 09/27/20 | Seattle Mariners optioned RHP Seth Frankoff to Mariners Alternate Training Site. |
| 09/26/20 | Seattle Mariners recalled Seth Frankoff from Mariners Alternate Training Site. |
| 09/25/20 | Seattle Mariners claimed RHP Ian Hamilton off waivers from Chicago White Sox. |
| 09/25/20 | Seattle Mariners optioned RHP Ian Hamilton to Mariners Alternate Training Site. |
| 09/23/20 | Seattle Mariners placed CF Jake Fraley on the 10-day injured list. Right quad strain. |
| 09/23/20 | Seattle Mariners recalled CF Braden Bishop from Mariners Alternate Training Site. |
| 09/22/20 | Seattle Mariners recalled CF Jake Fraley from Mariners Alternate Training Site. |
| 09/22/20 | Seattle Mariners placed 3B Dylan Moore on the 7-day injured list. Concussion. |
| 09/17/20 | Seattle Mariners sent RHP Jimmy Yacabonis outright to Mariners Alternate Training Site. |
| 09/17/20 | Seattle Mariners invited non-roster RHP Jimmy Yacabonis to spring training. |
| 09/17/20 | San Diego Padres traded RHP Matt Brash to Seattle Mariners. |
| 09/16/20 | Seattle Mariners activated SS J.P. Crawford from the bereavement list. |
| 09/16/20 | Seattle Mariners activated SS J.P. Crawford from the bereavement list. |
| 09/16/20 | Seattle Mariners activated SS J.P. Crawford from the bereavement list. |
| 09/16/20 | Seattle Mariners activated SS J.P. Crawford from the bereavement list. |
| 09/16/20 | Seattle Mariners optioned 2B Donovan Walton to Mariners Alternate Training Site. |
| 09/16/20 | Seattle Mariners activated SS J.P. Crawford from the bereavement list. |
| 09/15/20 | Seattle Mariners activated RHP Brandon Brennan from the 60-day injured list. |
| 09/15/20 | Seattle Mariners designated Jimmy Yacabonis for assignment. |
| 09/15/20 | Seattle Mariners optioned RHP Seth Frankoff to Mariners Alternate Training Site. |
| 09/14/20 | Seattle Mariners optioned LHP Aaron Fletcher to Mariners Alternate Training Site. |
| 09/14/20 | Seattle Mariners activated RHP Erik Swanson from the 10-day injured list. |
| 09/14/20 | Seattle Mariners recalled 2B Tim Lopes from Mariners Alternate Training Site. |
| 09/11/20 | Seattle Mariners sent CF Mallex Smith outright to Tacoma Rainiers. |
| 09/11/20 | Seattle Mariners recalled Donovan Walton from Mariners Alternate Training Site. |
| 09/11/20 | Seattle Mariners recalled RHP Brady Lail from Mariners Alternate Training Site. |
| 09/11/20 | Seattle Mariners placed 2B Shed Long Jr. on the 10-day injured list retroactive to September 10, 2020. Right shin stress fracture. |
| 09/11/20 | Seattle Mariners placed SS J.P. Crawford on the bereavement list. |
| 09/09/20 | Seattle Mariners selected the contract of RHP Jimmy Yacabonis from Mariners Alternate Training Site. |
| 09/09/20 | Seattle Mariners optioned RHP Brady Lail to Mariners Alternate Training Site. |
| 09/07/20 | Seattle Mariners activated RHP Casey Sadler. |
| 09/07/20 | Seattle Mariners placed 2B Sam Haggerty on the 10-day injured list retroactive to September 5, 2020. Left forearm strain. |
| 09/05/20 | Seattle Mariners activated RF Phillip Ervin. |
| 09/05/20 | Seattle Mariners optioned CF Jake Fraley to Mariners Alternate Training Site. |
| 09/05/20 | Seattle Mariners claimed RHP Casey Sadler off waivers from Chicago Cubs. |
| 09/04/20 | Seattle Mariners activated 3B Dylan Moore from the 10-day injured list. |
| 09/03/20 | Seattle Mariners activated RHP Walker Lockett. |
| 09/03/20 | Seattle Mariners claimed RF Phillip Ervin off waivers from Cincinnati Reds. |
| 09/03/20 | Seattle Mariners optioned 2B Tim Lopes to Mariners Alternate Training Site. |
| 09/02/20 | Seattle Mariners invited non-roster RHP Penn Murfee to spring training. |
| 09/02/20 | Seattle Mariners invited non-roster LHP Ian McKinney to spring training. |
| 09/01/20 | Seattle Mariners sent RHP Zac Grotz outright to Mariners Alternate Training Site. |
| 09/01/20 | Seattle Mariners sent RHP Zac Grotz outright to Tacoma Rainiers. |
| 09/01/20 | Seattle Mariners optioned CF Braden Bishop to Mariners Alternate Training Site. |
| 09/01/20 | Seattle Mariners activated 3B Ty France. |
| 09/01/20 | Seattle Mariners optioned C Joe Hudson to Mariners Alternate Training Site. |
| 09/01/20 | Seattle Mariners activated 3B Ty France. |
| 09/01/20 | Toronto Blue Jays traded RF Alberto Rodriguez to Seattle Mariners. |
| 09/01/20 | Seattle Mariners activated C Luis Torrens. |
| 09/01/20 | Seattle Mariners optioned 2B Donovan Walton to Mariners Alternate Training Site. |
| 09/01/20 | Seattle Mariners activated 3B Ty France. |
| 09/01/20 | Seattle Mariners activated 3B Ty France. |
| 09/01/20 | Seattle Mariners activated 3B Ty France. |
| 09/01/20 | Seattle Mariners activated 3B Ty France. |
| 09/01/20 | Seattle Mariners claimed RHP Walker Lockett off waivers from New York Mets. |
| 09/01/20 | Seattle Mariners activated RHP Kendall Graveman from the 10-day injured list. |