Grossman left in the first quarter with a knee injury, and the Bears said he would not return. His left leg twisted awkwardly when he was driven into the ground by defensive lineman Cornelius Griffin.
The injury happened on Chicago's second possession, slightly more than four minutes into the game.
Grossman was 2-for-6 for 14 yards. He was replaced by Brian Griese.
Early in the second quarter, Bears defensive tackle Antonio Garay left with an ankle injury. Chicago said he wouldn't return, either.
Campbell was carted off with a dislocated left kneecap in the second quarter. His left leg buckled when he was hit by defensive end Mark Anderson, one of three Bears defenders who converged on Campbell as he completed a pass.
Two plays before Campbell left for good, Redskins tight end Chris Cooley was injured. He later limped to the locker room but returned for the start of the second half.
Redskins right guard Randy Thomas, who had been out since Week 2 with a torn left triceps, returned to the starting lineup Thursday, but he left in the first half with an elbow injury. The team said his return was questionable.