Priester (3-6) pitched five innings of one-run ball to pick up the win Sunday against the Rays, allowing four hits and one walk while striking out two.
Priester was recalled from Triple-A Worcester on Sunday ahead of his start against the Rays.
Priester is an option to start for the Red Sox on Sunday versus the Rays, Mac Cerullo of the Boston Herald reports.
The Red Sox acquired Priester from the Pirates on Monday in exchange for Nick Yorke, Jeff Passan of ESPN.com reports.
Priester (2-5) allowed one earned run on three hits across two innings to earn the win Sunday against the White Sox.
The Pirates activated Priester (lat) from the 15-day injured list Tuesday.
Priester (lat) completed five innings while allowing one run on three hits and no walks with six strikeouts in a rehab outing with Triple-A Indianapolis on Tuesday.
Priester (lat) will begin a rehab assignment with Triple-A Indianapolis on Wednesday, Alex Stumpf of MLB.com reports.
Priester (lat) completed a bullpen session Tuesday and could face live hitters next, Andrew Destin of the Pittsburgh Post-Gazette reports.
The Pirates placed Priester on the 15-day injured list Thursday with a right lat injury, Alex Stumpf of MLB.com reports.