Washington Redskins head coach Mike Shanahan has confirmed on Monday that linebacker Brian Orakpo will miss the remainder of the season due to a tore pectoral muscles suffered in Sunday's 31-28 loss to the St. Louis Rams.

It was initially believed that the injury was just an aggravation of a previous pectoral tear and would only keep the linebacker out for a week or so, but Shanahan told the media on Monday that Orakpo had torn the muscle in a different location than was operated on over the offseason. He will require another surgery, ending his season.

Shanahan announced that the two-time Pro Bowl linebacker will undergo surgery this week and the team is expecting a four-month recovery period that will keep the fourth-year pro our for the rest of 2012.

The Redskins will use Rob Jackson and Chris Wilson in that linebacker position when they take on the Cincinnati Bengals in Washington's home opener on Sept. 23.

This is a significant loss for the Redskins, who also won't have defensive end Adam Carriker for the rest of the season with a torn quad tendon at the base of his knee.

"Adam's been a big part of what we've been able to do around here, a tremendous player for us. He's going to be done, I guess, for the rest of the year," middle linebacker London Fletcher said. "We'll miss him, but it's an opportunity for somebody else now. We're a no-excuse football team. Hey, injuries happen in the National Football League, so the next man has to come up and play well in that position."