The Seattle Seahawks have confirmed that Chris Clemons has torn his anterior cruciate ligament and meniscus.
The defensive end sustained the injury during the Seahawks' 24-14 win over the Washington Redskins on Sunday.
Head coach Pete Carroll told reporters: "It's a big loss for us in a lot of ways.
"Chris has been a great football player and just a symbol of consistency in the years that we've had him, but he's been a great leader for us, too, and a tough dude and a guy we've become very comfortable playing with, and we'll miss the heck out of him.
"This is [rookie Bruce Irvin's] opportunity. This is what we drafted him to play, and we'll see how he does. We expect him to do really well as he steps up."
Clemons has 11 sacks and 37 hurries this season, but will miss the remainder of the playoffs with the injury.
The Seahawks face the Atlanta Falcons on Sunday.
