"Plan A at middle linebacker crumbled during the embryonic stage of the season when starter Stewart Bradley was lost to a torn anterior cruciate ligament in his left knee.

Now, as the Eagles prepare for their sixth game of the season, against the Washington Redskins on Monday night at FedEx Field, they have been forced to Plan E at the position.

With Omar Gaither likely sidelined for a while by a foot injury, the Eagles completed a trade yesterday that brought them veteran linebacker Will Witherspoon from the St. Louis Rams. The deal, made just before the NFL's 4 p.m. deadline, sent rookie wide receiver Brandon Gibson and a 2010 fifth-round draft pick to St. Louis.

"I think [Gibson] is going to have a great career in the NFL," Eagles coach Andy Reid said during a conference call. "That doesn't make this an easy situation. We started off the season thinking we were in pretty good shape at [middle linebacker], and now we've been banged up a little here, so we needed to make this move to stay strong there. That's the only reason I would have done something like this."

Gaither's injury originally was described as a sprained foot, but Reid acknowledged yesterday that it could be something more severe. The fourth-year linebacker is scheduled to visit a foot specialist this week, the coach said.

Witherspoon, 29, will take over Gaither's role as the Eagles' primary middle linebacker.

"I'm bringing him in here as a [middle] linebacker to fill in what Omar did," Reid said. "I look at Will as a starter just like I did Omar."

Witherspoon was playing weakside linebacker in coach Steve Spagnuolo's defensive scheme with the Rams, but he spent his first three seasons in St. Louis as a middle linebacker. He also played both middle linebacker and weakside linebacker during his first four NFL seasons with Carolina.

"I'm definitely comfortable" playing middle linebacker," Witherspoon said. "It never bothered me one way or another. I'm a guy who wants to be on the field with an opportunity to make plays.""