Originally Posted by jerseyguy4
It is sort of like the difference between being lined in the neutral zone (not blown dead) and unabated to the QB (blown dead). I would guess the rule change was meant to protect the offense.
It was instituted after the superbowl last year. Late in the game the Giants had 12 men on defense and the Patriots ran a play. The play took quite awhile (8 seconds I think) and resulted in an incomplete pass. The argument was that the Giants had the luxury of an extra defender which made the play less likely to succeed, but still took a bunch of time off the clock.
So they changed it to a dead-ball foul so no time runs off unless the defender is running off because that gives the offense an advantage (a free play with 11-on-11).