The video from NFL officiating hit head coach and general manager inboxes on Tuesday.
For 106 seconds, a narrator explained league rules on reporting a change of position atop video clips from the controversial ending to the Detroit Lions-Dallas Cowboys game on Saturday night.
“It is the responsibility of the player to be sure that change in status is clearly communicated to the referee by both a physical signal with his hands up and down in front of his chest,” an automated voice said, “and to report to the referee his intention to report as an eligible receiver.