The Redskins’ defense needed good news. It got the worst instead: two-time Pro Bowler Brian Orakpo and starting left defensive end Adam Carriker are done for the season.

Orakpo tore a muscle in his left pectoral and Carriker tore his right quadriceps in Sunday’s 31-28 loss to St. Louis.

Both will require surgery — Carriker faces a six-month recovery period; Orakpo faces a four-month recovery.

Jarvis Jenkins will replace Carriker in the starting lineup while Rob Jackson and Chris Wilson will compete for Orakpo’s spot. Both played Sunday. Coach Mike Shanahan said they’ll likely promote defensive end Doug Worthington off the practice squad to take Carriker’s roster spot.

Orakpo injured his left pectoral muscle in the 2011 season finale and needed offseason surgery. He re-injured it this summer in the second preseason game. Shanahan said he tore a different part of the muscle Sunday.

Orakpo’s presence could alter the pass rush. The Redskins liked moving him around and he drew attention from opposing offenses that freed others. The Saints, for example, sent their tight end often Orakpo’s way.

“Obviously he’s a guy that can do it all,” Shanahan said. “He can cover, he can rush, he can play the run. He’s very physical. He’s very smart, a team player. All the things you’re looking in a Pro Bowl player. Obviously we’ll miss him.”