Hatcher will undergo arthroscopic surgery, which will be performed by Dr. James Andrews on Thursday, to clean up issues with the cartilage in his left knee. Hatcher said he'll miss four to six weeks, which would put his availability for training camp in jeopardy. The Redskins' first training camp practice is July 24.
"We don't feel it's a long-term thing," Redskins coach Jay Gruden said. "But anytime you have a surgery there's a little concern, but from what I'm told the severity of it is not that great. There's no damage in there whatsoever."
Hatcher, who will turn 32 on July 13, was signed by Washington this past offseason to bolster its inside pass rush. The four-year deal was worth $10.5 million guaranteed -- a $9 million signing bonus plus his $1.5 million base salary this season.
He's coming off a career-best 11 sacks with Dallas last season.
Hatcher said 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 (percent), so I can be the best Hatch for this football team."