Angels right-hander Kelvim Escobar has been dropped from the rotation after one start and sent to the bullpen due to a lack of stamina in his surgically repaired throwing shoulder.

Los Angeles manager Mike Scioscia said Escobar will not pitch again until the middle of next week. There is a possibility that Escobar, expected to be a reliever the rest of the season, could wind up on the disabled list.

"If he's not ready to pitch by the middle of next week then we'll have to DL him. We don't anticipate that," Scioscia said before Thursday night's game at Tampa Bay.

Escobar made his first major league start since 2007 last Saturday, allowing two runs and four hits in five innings against Detroit.

"He felt he didn't have the stamina to go out there and throw the 90 pitches and recover," Scioscia said. "So he's going to pitch out of the 'pen for that reason. He feels great up to a certain pitch count."

After going 18-7 for the Angels in 2007, Escobar underwent shoulder surgery last year and missed the entire season. He made three rehab starts in the minors this year.

With eighth-inning setup man Scot Shields out indefinitely with an injured left knee, Escobar could eventually help fill that role.

Right-hander Matt Palmer will replace Escobar in Friday night's game against San Diego.