Washington Redskins quarterback Robert Griffin III suffered a concussion in Thursday's preseason game against the Detroit Lions when he was hit while attempting to recover a fumble, coach Jay Gruden said.
Gruden said he was unsure when Griffin would be able to return to action but would be the team's starter when healthy. Griffin left the game with a stinger, but Gruden said that injury was not an issue.
Lions defensive end Corey Wootton tackled Griffin in the second quarter and appeared to land on the quarterback's shoulder. Griffin remained on the field for several minutes while medical staff attended to him, though he walked off with trainers and gave fans a thumbs-up signal.