Phillies closer Brad Lidge had successful arthroscopic surgery on his right knee Monday to repair a torn meniscus.
Lidge, Philadelphia's biggest offseason acquisition, limped off the field Saturday after injuring his knee when he caught a spike in the mound on his first pitch of batting practice. Doctors removed torn cartilage from the same knee in October.
"The other side of the knee is fine," Phillies trainer Scott Sheridan told ESPN.com's Jayson Stark on Monday. Sheridan called Lidge's injury and the subsequent successful surgery "the best-case scenario" for the Phillies.
Lidge, 31, is expected to be sidelined for three to six weeks. The Phillies open the season at home March 31 against Washington.
Phillies manager Charlie Manuel said set-up man Tom Gordon would close if Lidge isn't ready for Opening Day.
"Ideally, if everything went right I wouldn't miss any of the season because that would be four weeks," Lidge said. "But that will be based on how it feels."
Lidge and the Phillies' medical staff think he has a chance to come back from Monday's surgery and be ready for Opening Day. But Manuel sounds like a guy who isn't thinking that way.
"I don't want him to rush back" Manuel told Stark. "I want to make sure he's healthy. I want to make sure he's mentally and physically ready to perform top-notch"
Phillies assistant general manager Ruben Amaro Jr. said officials will make sure Lidge is healthy before he takes the mound.
"I know he'll be chomping at the bit, because he's looking forward to it and he's excited about the season, but ... that's our main goal, that he's healthy when he gets on the mound and pitches for the Phillies," Amaro said.
Manuel has been raving about the way Gordon and Ryan Madson have thrown. So if the Phillies have to play without Lidge for a while in April, expect Gordon to do most of the closing and Madson to assume Gordon's role as primary righthanded set-up man.
The Phillies acquired Lidge and infielder Eric Bruntlett in a November trade that sent outfielder Michael Bourn, infield prospect Mike Costanzo and reliever Geoff Geary to the Astros. Lidge, who has 123 career saves, finished 2007 with 19 saves in 27 chances and a 3.36 ERA for Houston.
When the Phillies acquired him, it allowed them to strengthen their rotation by making Brett Myers a starter again.
"Right now, if we had to do this during the season, then obviously you're missing a big chunk of the season," Lidge said. "I definitely need a few bullpen sessions, but I feel like my arm is ahead of schedule so after a week I should be able to throw again."
The Phillies struggled with injuries in the bullpen for much of last season. Gordon and Myers both missed significant time.
Information from The Associated Press and ESPN.com's Jayson Stark was used in this report.