A rushing defensive player who lowers his head and buries his helmet into the body of a defenseless quarterback will be called for a personal foul, NFL vice president of officiating Dean Blandino explained in his Dec. 19 video for the media.

Blandino provided three examples of quarterback hits to demonstrate the difference between legal and illegal hits. Under the rules, a defender cannot use the crown or forehead part of the helmet to make forcible contact with a passer judged to be in a defenseless position.

He also reviewed plays from the Washington-New York Giants, Green Bay-Buffalo, Miami-New England and New York Jets-Tennessee games on Dec. 14.