NFL officials threw only one flag for the league's new use of helmet rule during the first 14 games of Week 1, another sign that the penalty will not impact the regular season as deeply as once feared.

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.

Two Week 1 games remain to be played. But barring a surge of flags Monday night, the NFL will have orchestrated a significant drop in helmet rule penalties since a chaotic summer.

During the first 33 games of the preseason, officials called 51 helmet rule fouls, an average of 1.55 per game. After the competition committee issued a narrow clarification Aug. 22 to remind officials to avoid penalizing inadvertent or incidental contact, the number dropped by nearly 60 percent.

There were nine such penalties in Week 3 of the preseason and 11 in Week 4, for a combined average of 0.625 per game.

NFL officials have said they hope the helmet rule will eventually change the way football is played. Al Riveron, the league's senior vice president of officiating, said last month the league wants the emphasis against lowering the head in contact to trickle down to lower levels of the game.

At the same time, however, the NFL has tried to make clear that it did not expect the changes to happen in one season -- and never intended this season's games to be overrun by penalties. NFL executive vice president Troy Vincent said in May that it was "truly unrealistic" to expect overnight compliance.

In the end, the preseason spike in flags might be best viewed as a consequence-free setting of parameters for future technique development.

"There are certain things that are incidental contact and just part of this sport," 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."