OXNARD, Calif. -- Dallas Cowboys defensive end Anthony Spencer is having arthroscopic surgery on his left knee and is likely to miss the rest of training camp.
Spencer said he will have surgery Thursday in Dallas and expects to miss three weeks, which puts his return about the same time the Cowboys break camp before their third preseason game at Arizona.
"I have a lot of time," Spencer said Tuesday. "I feel like I will definitely be ready before the season gets here."
Spencer hyperextended the knee in off-season workouts and said he aggravated the injury in the conditioning test before training camp. He has described the injury as a bone bruise and said the surgery was to clean up some of the tissue around the knee.
"We don't think it's a very severe thing," coach Jason Garrett said. "We thought getting it cleaned up sooner rather than later was better for him and for our team."
The 29-year-old Spencer had a similar procedure in late August in 2008 but missed only one regular-season game. Dallas breaks camp Aug. 16.
He was the leading tackler last season and finished a half-sack behind DeMarcus Ware with a career-high 11.
Spencer is playing on a one-year contract under the franchise tag for the second straight season. This year's deal is worth $10.6 million.