Mariners Roster & Staff
Transactions
| Date | Transaction |
| 04/30/19 | Seattle Mariners signed free agent RHP Natanael Garabitos to a minor league contract. |
| 04/30/19 | Seattle Mariners recalled Braden Bishop from Tacoma Rainiers. |
| 04/30/19 | Seattle Mariners optioned CF Mallex Smith to Tacoma Rainiers. |
| 04/28/19 | Baltimore Orioles claimed RHP Shawn Armstrong off waivers from Seattle Mariners. |
| 04/27/19 | Seattle Mariners optioned LHP Justus Sheffield to Tacoma Rainiers. |
| 04/27/19 | Seattle Mariners activated RHP Mike Wright. |
| 04/26/19 | Seattle Mariners recalled Justus Sheffield from Tacoma Rainiers. |
| 04/26/19 | Seattle Mariners designated RHP Shawn Armstrong for assignment. |
| 04/25/19 | Seattle Mariners selected the contract of LHP Jonathon Niese from Long Island Ducks. |
| 04/24/19 | Baltimore Orioles traded RHP Mike Wright to Seattle Mariners for SS Ryne Ogren. |
| 04/24/19 | Baltimore Orioles traded RHP Mike Wright to Seattle Mariners for SS Ryne Ogren. |
| 04/23/19 | Chasen Bradford roster status changed by Seattle Mariners. |
| 04/22/19 | Seattle Mariners optioned RHP R.J. Alaniz to Tacoma Rainiers. |
| 04/22/19 | Seattle Mariners signed free agent LHP Elniery Garcia to a minor league contract. |
| 04/19/19 | Seattle Mariners selected the contract of RHP Tyler Cloyd from Somerset Patriots. |
| 04/19/19 | Seattle Mariners selected the contract of RHP Christian Bergman from Sugar Land Skeeters. |
| 04/15/19 | Seattle Mariners signed free agent RHP Juan Burgos to a minor league contract. |
| 04/14/19 | Milwaukee Brewers traded RHP Sal Biasi to Seattle Mariners for C David Freitas. |
| 04/14/19 | Seattle Mariners recalled Erik Swanson from Tacoma Rainiers. |
| 04/14/19 | Milwaukee Brewers traded RHP Sal Biasi to Seattle Mariners for C David Freitas. |
| 04/14/19 | Seattle Mariners placed LHP Wade LeBlanc on the 10-day injured list. Strained right oblique. |
| 04/12/19 | Seattle Mariners optioned RHP Erik Swanson to Tacoma Rainiers. |
| 04/12/19 | Seattle Mariners optioned RHP Matt Festa to Tacoma Rainiers. |
| 04/12/19 | Seattle Mariners recalled R.J. Alaniz from Tacoma Rainiers. |
| 04/12/19 | Seattle Mariners activated RHP Shawn Armstrong from the 10-day injured list. |
| 04/09/19 | Seattle Mariners placed RHP Chasen Bradford on the 10-day injured list. Right shoulder inflammation. |
| 04/09/19 | Seattle Mariners recalled Erik Swanson from Tacoma Rainiers. |
| 04/03/19 | Seattle Mariners optioned RHP Nick Rumbelow to Tacoma Rainiers. |
| 04/03/19 | Seattle Mariners sent RHP Shawn Armstrong on a rehab assignment to Tacoma Rainiers. |
| 04/03/19 | Seattle Mariners activated RHP Connor Sadzeck. |
| 04/02/19 | Seattle Mariners transferred RHP Hunter Strickland from the 10-day injured list to the 60-day injured list. Right lat strain. |
| 04/02/19 | Seattle Mariners optioned RHP David McKay to Tacoma Rainiers. |
| 04/02/19 | Texas Rangers traded RHP Connor Sadzeck to Seattle Mariners for RHP Grant Anderson. |
| 04/02/19 | Texas Rangers traded RHP Connor Sadzeck to Seattle Mariners for RHP Grant Anderson. |
| 04/02/19 | Seattle Mariners activated RHP Anthony Swarzak from the 10-day injured list. |