Pomeranz has struggled this season, allowing at least four runs in each of his last three starts. He's 1-3 with a 6.81 ERA overall.
Pomeranz was scheduled to start Thursday against the Detroit Tigers. The Red Sox said they will recall left-hander Jalen Beeks from Triple A Pawtucket to start that game.
Beeks, who will be making his major league debut, is 3-3 this season with a 2.56 ERA. He has struck out 80 and walked 14 in 56 1/3 IP.
Knuckleballer Steven Wright made his first start of the season Tuesday and threw seven two-hit innings in a 6-0 shutout of the Tigers. He is expected to remain in the rotation for the time being.
Red Sox second baseman Dustin Pedroia, on the disabled list with a sore left knee, got some good news when the doctor who had performed surgery on the knee did not find anything wrong beyond inflammation.
Manager Alex Cora said Pedroia, 34, is expected to resume baseball activities in the next couple days. The four-time All-Star went back on the DL on Saturday, after playing just three games since coming back from offseason surgery.
The Red Sox recalled right-handed reliever Brandon Workman from Pawtucket on Tuesday to take Pomeranz's spot on the roster.