Redskins safety Brandon Meriweather is expected to miss at least one game after he reinjured his knee in an odd pregame collision with teammate Aldrick Robinson before Sunday's game.
Meriweather was expecting to make his 2012 debut on Sunday after missing the first three games with knee injury.
But while he was running down a pass during pregame warm-up, Meriweather collided with Robinson, a wide receiver who was stretching on his own in the end zone.
Redskins coach Mike Shanahan said Monday that Robinson was knocked out for more than a minute. He is being monitored to determined whether he sustained a concussion, the Washington Post reported. Robinson had played in the three previous games, including one start, and had seven catches this season.
Meriweather reinjured both his medial collateral ligament and his posterior cruciate ligament in his left knee in the collision. He is unlikely to play in Washington's next game against the Falcons on Sunday, the Post reported, and his status beyond that is uncertain.