ANAHEIM, Calif. — Angels' reliever Scot Shields will have season-ending surgery on Tuesday, manager Mike Scioscia said before the game against the San Diego Padres.

Shields, who was placed on the disabled list on May 27 for patella tendinitis, said rehab wasn't doing the trick and that the pain in his left knee was too much to bear. The decision to undergo the procedure was made last weekend when the Angels played the Detroit Tigers on the road.

"It's tough," Scioscia said. "It's something he's dealt with occasionally and it's gotten to a point where it needs to be taken care of."

Shields put together a solid year in 2008, posting a 2.70 ERA with a 6-4 record as the bullpen's workhorse.

But he had given up runs in eight of his 20 appearances, and had three losses and three blown saves before being placed on the DL this season. His 42 wins as a reliever are the most in franchise history.

"Right now we're going to have to go by committee," Scioscia said.