Gonna put the tin foil hat on for a second.
Dunno if you guys remember, but it seems like a minute or two before Cassel got hurt, they showed him on the bench talking on the phone. Who was he talking to? Daboll is on the sidelines. Zorn maybe?
Any chance it was someone telling him that he's gonna have to do something to get out of this game. He can't finish it, being the sole reason for the loss. So, he goes down with a concussion, without getting hit in the head.