Referee Jerome Boger has his hands full with some controversial calls, most notably, a rarely used call on the Giants drive for the game-winning touchdown (video). Giants receiver Victor Cruz lands to the turf and walks back to the huddle as if the play was over. However, he was not contacted on the way to the ground, so ordinarily, this remains a live ball. The ruling on the field, as explaned by Boger:
The ruling on the previous play was that the receiver gave himself up by going to the ground. That cannot be challenged. So there is no challenge allowed by Arizona. It is first down, New York.
From the video, it appeared as if the initial ruling was made by headlinesman Jerry Bergman. (Back judge Tony Steratore is shown in a replay covering the play as a fumble, but he did not throw his beanbag marker that would indicate he was ruling it that way.)
From the NFL Rulebook, Rule 7, Section 2, Article 1:
An official shall declare the ball dead and the down ended:
(e) when a runner is out of bounds, or declares himself down by falling to the ground, or kneeling, and making no effort to advance
A player need not slide, as what was commented on some broadcast outlets, in order to qualify for declaring himself down under Item (e), because the criteria for a slide is contained in Item (d).
The fact that Cruz stayed to the ground for a brief period allows this interpretation of declaring himself down to be made. But was he down long enough?
Take another example where a player on the receiving team catches an onside kick. He secures the catch and immediately flops to the ground. Play is over immediately, because the receiver declared himself down. In the case of Cruz’s open-field catch, he must demonstrate an intention to change his status from runner to declared down. In Cruz’s case, we would expect to see him down longer than the hypothetical onside-kick receiver who is never considered a runner.
It is an issue of perception, just like when a player’s forward progress is stopped. Once the official makes that snap judgment that the player is giving himself up, there is no swallowing of the whistle, even if contrary evidence is provided.