Redskins running back Chris Thompson, who has been inactive the past four games while battling a shoulder injury, will be placed on injured reserve, Coach Mike Shanahan.

“He’ll be on IR before next game, so he’s definitely out,” Shanahan said, adding that the rookie will undergo surgery to repair his labrum.

“I don’t think we’ll know exactly [what's wrong] until they look at it,” Shanahan added. “It’s something that’s been ongoing. It’s got a little bit worse. So doctors recommended that he has surgery on it.”

Shanahan did not specify when the injury occurred, but said Thompson’s left shoulder has been bothering him for “some time.” In August, Thompson had his shoulder pop out and back in during a preseason game against the Steelers.