Washington Redskins rookie quarterback Robert Griffin III sustained a mild concussion in a Week 5 loss to the Falcons. According to Jim Corbett of USA Today, Griffin did not know the score or what quarter it was when the Washington training staff put him through the initial tests.

The dynamic rookie went to slide in the third quarter and was hit high by Atlanta linebacker Sean Witherspoon. RGIII's upper body snapped back and his head slammed into a pursuing Jonathan Babineaux. An animated gif of the play:

He immediately left the field and was replaced by Kirk Cousins. Redskins head coach Mike Shanahan confirmed after the game that it was a mild concussion. RGIII's locker was promptly cleared out after the game, and he was not available to the media, per NFL protocol.

Griffin III was 10 of 15 for 91 yards on the day. The Redskins had been questioned in September about the volume of designed runs for the rookie, but he had only one carry for seven yards in the game -- the play that resulted in the injury.

This story originally appeared on SBNation.com.