Didn't Kam punch the ball from Calvin Johnson? Don't defensive players frequently try to punch the ball away?
According to this, punching is against the rules.
I think what everybody learned last night (the NFL, ESPN, football fans) --- the NFL has some confusing language with punched/batted balls, and they should probably clean-up the rules. Otherwise, you're going to have confused refs, and confused fans. One man's punch is another man's legal fumble.
http://www.nfl.com/rulebook/useofhands
A player may not bat or punch:
(a) A loose ball (in field of play) toward his opponent’s goal line or in any direction in either end zone.
(b) A ball in player possession.
Note: If there is any question as to whether a defender is stripping or batting a ball in player possession, the official(s) will rule the action as a legal act (stripping the ball).
Exception: A forward or backward pass may be batted, tipped, or deflected in any direction at any time by either the offense or the defense.
Note: A pass in flight that is controlled or caught may only be thrown backward, if it is thrown forward it is considered an illegal bat.
No player may deliberately kick any ball except as a punt, dropkick, or placekick.