Aloha, Oklahoma drills.
The NFL has eliminated various types of high-contact drills from training-camp practices, including the Oklahoma drill and bull in the ring.
The move is the next step in the evolution of the game, as the league hopes to identify and to remove any and all situations that entail unnecessary helmet contact.
The Oklahoma drill is a key aspect of old-school football practice. Consider the reverence with which players and coaches spoke of the exercise only six years ago, when the Bengals returned to Hard Knocks. (Seriously, click that link and watch it.) Still, this change didn't come from the ivory tower on 345 Park Avenue; coaches were directly involved in identifying and embracing the elimination of these concussion-inducing plays.
The reason for doing it is simple. As the NFL tries to lead the way in making the sport safer at every level (so that people will choose to play it at every level), the NFL needs to get rid of certain dangerous drills, and to hope that college, high school, and youth football will do the same.