NFL referees made just one call under the new helmet-hitting rule in Week 1. (Jeff Haynes/AP Images for Panini)

There was a bit of an uproar over the NFL’s new helmet-hitting rule, ratified in March without advance warning and hailed as a major player-safety change, when the penalty flags were flying with regularity early in the preseason.

Observers wondered whether the flag-fest would continue into the regular season and tried to figure out just how much the new rule would impact games.

If Week 1 of the season was any indication, the fretting was unwarranted.

In 16 games leaguewide, beginning with Thursday night’s season opener in Philadelphia and concluding with Monday night’s doubleheader, there was only one penalty called under the new rule, which makes it illegal for a player to lower his head and use his helmet to initiate contact with an opponent. That 15-yard penalty was assessed Sunday against Kansas City Chiefs safety Ron Parker.

Cincinnati Bengals safety Shawn Williams was ejected Sunday for a helmet-to-helmet hit on Indianapolis Colts quarterback Andrew Luck. The ejection was confirmed via instant-replay review by Al Riveron, the NFL’s senior vice president of officiating.

But Williams was ejected for unnecessary roughness, according to the league, not for a violation of the new helmet-hitting rule. When the league put the final piece of the new rule in place in May and approved the use of replay to help determine if a player should be ejected, it actually made all ejections subject to replay review, not only those under the helmet-hitting rule.

The dearth of Week 1 calls involving the new rule came after a preseason in which there were 71 penalties called under the helmet-hitting rule in 65 games, an average of 1.09 per game. But even during the preseason, there was a sharp decline in calls after the midway point. There were 51 penalties under the new rule in 33 games in the first two weeks of the preseason, including the Hall of Fame Game. Over the final two weeks, there were 20 such penalties over 32 games.

The onslaught of calls early in the preseason led to outcry by some players, fans and media members. They called the rule unfair to players and too difficult to officiate properly. Some even called for the league to rescind the rule before the season.

But the NFL stood by the rule, having called it a significant and necessary safety measure designed to get an unsafe hitting technique out of the sport. Members of the league’s rule-making competition committee spoke via conference call midway through the preseason and announced that the rule would remain unchanged. But the NFL also issued a clarification saying that inadvertent or incidental contact would not result in a penalty.

In truth, those who designed the rule never intended for incidental contact to result in a penalty. The league’s rule makers envisioned a transition period for players, coaches and fans to adjust. They compared it to the adjustment period required when the league’s rules prohibiting hits to the head of a defenseless player first were implemented in the 1990s.

That’s why the pattern should have been predictable: The calls would come early and often during the preseason. Fans and some players would predict the demise of the sport. And then the season would arrive, adjustments would be made, and everything would calm down.

“We know that they’re gonna over-officiate it in preseason,” Colts Coach Frank Reich said during the preseason. “I think we welcome that because I think we all know that the helmet as a weapon is not good for the game. Nobody wants it — coaches, players, fans. So if it takes over-officiating it a little bit in preseason to help us get it right, then I think we have to live with that and just understand that’s gonna happen.”

The NFL does not want the new rule to fade away, though. League officials said they did not want this to be a repeat of the implementation of a previous ban on using the crown of the helmet to deliver a hit, a penalty that seldom was called.

This rule was enacted following a 2017 season in which concussions suffered by players were up, and in which Pittsburgh Steelers linebacker Ryan Shazier suffered a spinal cord injury on a hit in a December game. The NFL wants this rule to prompt players to change the way they hit, eventually trickling down to all levels of the sport.

It’s a delicate balance the NFL is attempting to strike, changing the way the sport fundamentally is played without having the quality of the on-field product diminished to a meaningful degree in the eyes of fans. It is a story line that is likely to remain prominent all season, even with the lack of penalties assessed on the opening weekend.

Read more NFL coverage

The Los Angeles Rams are your best play in eliminator and survivor pools for Week 2

Antonio Brown apologizes for threatening ESPN writer as Steelers are awash in drama

NFL Week 2 ATS picks: The top games worth betting on

Here’s what fantasy football owners should do with Le’Veon Bell

Nobody knows comebacks like Colts Coach Frank Reich: ‘You’ve always got to believe’