The NFL released the following explanation for referee Jerome Boger's ruling that New York Giants receiver Victor Cruz did not fumble against the Arizona Cardinals in Week 4:
"In Sunday’s game between the New York Giants and Arizona Cardinals, the Giants faced a 1st-and-10 from the Arizona 48 with 3:10 remaining in the fourth quarter. Quarterback Eli Manning connected with wide receiver Victor Cruz for a 19-yard gain.
"Referee Jerome Boger announced the following: '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.'
"The applicable rule in the 2011 NFL Rule Book is found on page 35.
"Rule 7, Section 2, Article 1 states that '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.' "
This is a judgment call, in other words. There is no specific set of requirements a runner must satisfy when declaring himself down. That means a runner can be declared down even if he slips to the ground, provided the referee thinks the runner meant to declare himself down on the play.
Cue the video to see the play.