Trevor Rosenthal will have Tommy John surgery on his right elbow, the St. Louis Cardinals have announced.

"I think just the timing of it, being right in the middle of this race and the way my personal season had been taking shape and the way the team has been playing recently. Tough timing," Rosenthal said.

"It felt like we were getting in a groove, I was in a groove, and to kind of have this happen and take a piece away from a really good team is a little bit of a bummer."

Rosenthal, who recorded 93 saves over the 2014 and 2015 seasons, lost the closer's job to Seung-Hwan Oh a year ago but regained it this season after Oh struggled.

Rosenthal will have surgery next week.

"We hoped for better news," Mike Matheny said. "Somebody is going to have to step in. He was really throwing the ball well."