The Redskins have been spared serious injuries this training camp, but the bug is still going around. Chris Cooley missed the Redskins afternoon walk-through Wednesday, the same day Redskins Coach Mike Shanahan conceded the team is worried about the tight end’s ailing knee.

“There is concern,” Shanahan said. “The knee is sore. He’s getting treatment and hopefully he keeps getting better.”

After missing two practices, Cooley returned to action Tuesday. But after just one day of work, he was unable to participate in Wednesday morning’s practice and was absent from the afternooon walk-through.

Cooley underwent surgery following last season to repair a torn meniscus. It has been bothering him in training camp, and Cooley had to have it drained last week. Fred Davis has been taking reps with the first-team in Cooley’s place.

Shanahan said Cooley will not play Friday against the Steelers. The team will also be without starting running back Ryan Torain (hand). Quarterback John Beck (groin) may have to miss the game as well.