Remember when New England Patriots receiver Julian Edelman caught a pass from quarterback Tom Brady with just under 11 minutes left in the fourth quarter of Super Bowl XLIX? Remember how he was then knocked down by a head-first hit to the side of his helmet? Remember that he stayed in the game and ended up catching the winning touchdown pass? You may remember all of this. It is not clear that Edelman does, though, because he may well have suffered a concussion.