Washington Redskins defensive end Jason Hatcher will undergo arthroscopic surgery on his left knee Thursday and will be out four to six weeks, according to reports Wednesday.

The surgery which will be performed by Dr. James Andrews to clean up issues with his cartilage in his knee. Hatcher's availability for training camp may be in jeopardy, with the first practice on July 24.

Hatcher had some tests on his knee Tuesday after he reported some pain and swelling.

"You know we'll see with Dr. Andrews and (head athletic trainer) Larry (Hess) after the surgery, but we don't feel like it's a long-term thing," Redskins coach Jay Gruden said. "But any time you have a surgery, there is a little bit of concern but I think that from what I have been told the severity of it is not that great."

The Redskins signed Hatcher, who will turn 32 on July 13, to four-year deal with $10.5 million guaranteed. He is coming off a career-best 11 sacks with the Dallas Cowboys last season.

Hatcher told ESPN.com he does not know when he suffered the injury.

"I know I did something. A lot of it is old stuff that just needs cleaning up," Hatcher said. "It's just cartilage floating around. Nothing major. I'll be ready for training camp. (Doctors and trainers) thought it best for me to do it if I don't want to be struggling through the season and be full strength. If I'm better, our defense is better.

"I don't want to go into the season 80 percent. I want to be 100 so I can be the best Hatch for this football team."