The penalty was assessed against Kansas City Chiefs defensive back Ron Parker for lowering his head to initiate contact with an opponent. 

Sunday’s ejection of Cincinnati Bengals safety Shawn Williams was for unnecessary roughness, not the helmet rule, according to the league.

The league acknowledged it wasn’t possible to implement such a drastic change in just one offseason when opting to limit the number of flags that would be thrown.

“There are certain things that are incidental contact and just part of this sport,” NFL executive vice president Troy Vincent said. “There are certain things you just have to live with and be OK with. And then there is the part of our role and responsibility. What do we want to coach out and then the players have to adjust to? Some of these things are more long term.

“To think that an individual player will make some of the adjustments between May 1 and the start of the season, when this is what I have done all of my life? That’s unrealistic. That’s truly unrealistic.”

Players will adjust, and by the looks of it, already have. It’s only a matter of time before muscle memory kicks in during play.