It's Hembree's second IL stint this season with a right elbow injury. He was out from mid-June until July 4 with an extensor elbow strain. In nine innings since returning from that first stint, Hembree allowed nine earned runs (10 total), including three home runs.
Hembree pitched an inning on Thursday, allowing a solo home run to Austin Meadows, as well as a single and a walk.
"It's the same thing as last time [on the IL]," Hembree said.
Hembree said he had an MRI on the elbow, which came back clean, but said that his pain never fully disappeared when he returned from the injured list the first time.
"I can't say it was ever fully completely gone. It was there, but I felt like I was good enough to pitch," he said.
"We're concerned," manager Alex Cora said. "We kept talking about his fastball, and people were talking about velocity, and I kept talking about location, where the fastball was. You can see, Heath is a guy that when he's good, he can locate that fastball in the zone. He wasn't able to do that yesterday."
Hembree said he hopes to return this season and doesn't see this as a season-ending injury.
"Hopefully this is something that is not long term," his manager echoed. "But we have to be careful. When he came back, we thought it wasn't going to happen again, that he was fine. And look what happened now."
Price on paternity list
The Red Sox also placed David Price, who is scheduled to start Sunday night's game, on the paternity list and recalled Marco Hernandez from Triple-A. Price joins his counterpart among Sunday's scheduled starters, J.A. Happ of the Yankees, on the paternity list -- Happ was also placed on that list today.
Cora said he still hopes that Price will still be able to start Sunday's game.