Green Bay Packers rookie running back Eddie Lacy and Washington Redskins safety Brandon Meriweather were knocked out of Sunday's game with concussions.
Lacy was injured at the end of his first carry of the game, a 10-yard run on the Packers' opening series. Lacy was hit helmet-to-helmet by Meriweather, who was not penalized on the play.
Meriweather later left the game in the second quarter with a helmet-to-helmet hit on Lacy's replacement, James Starks.
Starks and rookie Johnathan Franklin are the Packers' only available running backs.