ASHBURN, Va. -- Washington Redskins linebacker Ryan Kerrigan underwent arthroscopic surgery on his left knee Tuesday, leaving in doubt when he'll be able to resume his offseason activity.

Kerrigan said via text message that the procedure was "cautionary ... to make sure it's not a problem down the road." He said the knee just needed to be cleaned up and that he would be re-evaluated next week to determine when he might resume offseason work. The Redskins begin their organized team activities next week and have a minicamp June 16-18.

Kerrigan, entering the last year of his contract, has been talking to the Redskins about an extension, and general manager Scot McCloughan made it clear earlier this month that he wants to keep Kerrigan around.

"He's what I look for in a football player. Every day he's there trying to make himself better," McCloughan said.

Kerrigan is coming off his most productive season when it comes to sacks with a team-best 13.5.