CLEARWATER, Fla. — Philadelphia Phillies closer Brad Lidge is expected to miss three to six weeks after having surgery today on his right knee. The team said the operation was successful.

The 31-year-old right-hander, Philadelphia's biggest offseason acquisition, caught a spike in the mound on his first pitch of batting practice Saturday. Doctors removed torn cartilage from the same knee in October.

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.

Lidge, who has 123 career saves, finished 2007 with 19 saves in 27 chances and a 3.36 ERA for Houston.