Garrett (7-4) took the loss Thursday against the A's, allowing two runs on three hits and a walk in one inning. He struck out one.
The Mets activated Garrett (elbow) from the 15-day injured list Saturday, Mike Puma of the New York Post reports.
Garrett (elbow) will rejoin the Mets in Seattle on Friday, Tim Healey of Newsday reports.
Garrett (elbow) allowed one hit and one walk but struck out three over a scoreless inning in his first rehab appearance with Triple-A Syracuse on Tuesday.
Garrett (elbow) has been cleared to begin a rehab assignment with Triple-A Syracuse on Saturday after touching 97 mph in a live batting practice session Wednesday, Joe Pantorno of amNewYork Metro reports.
Garrett (elbow) hopes to be ready to throw a bullpen session by this weekend, Mike Puma of the New York Post reports.
Garrett (elbow) began a throwing progression Saturday, Tim Healey of Newsday reports.
MRI results on Garrett's right elbow revealed no ligament damage Thursday, Tim Britton of The Athletic reports.
The Mets placed Garrett on the 15-day injured list Wednesday with right elbow inflammation, Anthony DiComo of MLB.com reports.
Garrett gave up a hit and struck out one in a scoreless eighth inning Sunday to record his seventh hold of the season in a win over the Cubs.