Two people intimately involved in the situation -- head coach Andy Reid and Jamaal himself -- have said that Charles is fine following the brief injury scare.
Pro Football Talk reports that those two and a league source confirm that Charles is fine and his injury is not a big deal.
I suspected the injury wasn't serious because Charles did come back for a carry after he initially left and the Chiefs had the game in hand in the fourth quarter, leaving little reason to play Charles anyway. As the TV broadcast explained, that he was on the exercise bike suggests a muscle just tightened up.
The KC Chiefs running back initially went down with a quad injury in the third quarter. He was helped off the field but returned to carry the ball once on the last play of the third quarter. He sat out the rest of the game with the injury.
So he's fine. We'll continue to freak out because, hey, it's Jamaal ... but he's fine.