PHILADELPHIA -- Brewers reliever David Riske faces the prospect of season-ending Tommy John elbow ligament replacement surgery, but will try a three-week course of rehab before deciding to go under the knife.

Riske is on the disabled list because of looseness in the ulnar collateral ligament in his right elbow, and the decision to try rehab was made after Riske visited with noted orthopedist Dr. Lewis Yocum on Monday in Los Angeles. Yocum concurred with the original diagnosis from Brewers head physician William Raasch, who believes that Riske could strengthen the joint to the point of avoiding surgery.

"It's not torn. If it were torn, then it would be an automatic decision to repair [with surgery]," Brewers assistant general manager Gord Ash said. "But because it's not torn and there is only very minor laxity to it, the idea is to try to rehab it for three weeks or so to see if you can strengthen the area around it. If not, then he might be facing a surgery."

Riske did undergo surgery last season to remove a bone spur from his right elbow. He pitched though pain related to the spur for most of the year and finished with a 5.31 ERA in 45 appearances.

He was eager for an opportunity to bounce back in 2009, but surrendered two runs to the Giants in his only appearance before going to the DL. Riske will rejoin the Brewers on Friday in Houston and then will work out in Milwaukee from Monday through at least May 14 before the surgical option is revisited.

Riske is under contract this season and next as part of a three-year deal with the Brewers. Even if he avoids surgery this season, there are no guarantees that he's in the clear for 2010, according to Ash.

"If he can strengthen it to the point where he can make some contribution this year, then you've still got time to do surgery for his next contract," Ash said.

Riske is earning $4.25 million this season and is due $4.5 million next year as part of his $13 million deal.