Brian Johnson will stay in the rotation and will start in Philadelphia, Cora added.
The move comes with the expected return of Chris Sale this weekend, with David Price, Rick Porcello and Nathan Eovaldi staying in the rotation, and lefties Johnson and Pomeranz battling for the last spot.
With the Red Sox on an historic roll, Pomeranz has disappointed this season, going is just 1-5 with a 6.31 ERA in 51 1/3 innings pitched this season. In 2017, Pomeranz finished 17-6 with a 3.32 ERA.
The Red Sox are 81-34 entering Thursday's game at Toronto.