[footballfever]

I wasn't there but here is what the rules say:

Rule Book Non contact unsportsmanlike conduct by player:
Rule 9 Sec 5 Art f:
Leaving the field between downs to gain an advantage unless replaced or unless with permission of game official.

Case Book 9.6.4 situation B:A1 and A2 enter the field while A3 A4 and A5 move toward the sideline. A5 stops within the 9-yard marks while A3 and A4 continue toward the team box.The ball is blown ready for play with A3 and A4 outside the 9-yard marks and is snapped without a huddle and the QB throws a forward pass to A4, who has gone downfield as wide receiver.
Ruling: This play is illegal because a pretended substitution is used to deceive the opponents. The penalty of 15 yards for the illegal participation foul will be administered from the previous since foul occurred at the snap.