Bucannon's hit took place in the second quarter of Philadelphia's 24-20 loss to Arizona. Maclin caught a short pass from Nick Foles only to be immediately contacted in the helmet by Bucannon, who was leading with his helmet. The hit caused both Maclin and Cardinals cornerback Patrick Peterson, who was also in coverage of the Eagles wide receiver, to leave the game. Bucannon lost his helmet but remained in the game. Maclin cleared a concussion test and returned to the game while Peterson did not return.
Here's a GIF of the play.
The NFL must have somehow ruled Maclin was NOT a defenseless receiver. Here's the rule regarding defenseless receivers via the NFL Rulebook, Rule 12, Section 2, Article 17:
A receiver attempting to catch a pass; or who has completed a catch and has not had time to protect himself or
has not clearly become a runner. If the receiver/runner is capable of avoiding or warding off the impending
contact of an opponent, he is no longer a defenseless player
I'm guessing the NFL ruled Bucannon's hit to Maclin's head incidental because of the way Peterson was involved in the play. But who knows.
Legal hit or not, this is clearly the kind of play the NFL should be aiming to avoid. Both players motionless laid on the ground for several moments before finally getting up. Not exactly a pretty sight.
In other fine related news, Eagles outside linebacker Trent Cole was fined $22,050 for a tacky illegal hit on Carson Palmer.