Hal Hunter, the Giants’ offensive line coach, said officials are trying to prevent players from tackling defenders on every snap. He tells his players that if they are restricting someone’s movement, they are going to be called for holding.

“If you coach bad fundamentals and you play with bad fundamentals, it’s going to catch up to you,” he told reporters . “One thing that we’ve never tried, we’ve never taught holding. We don’t teach that type of stuff.”

But others admit that the focus on holding will change the way they play.

“We can always improve our technique and fundamentals,” said Dowell Loggains, the Jets’ offensive coordinator. “We need to do that with a sense of urgency.”

Officials are going to call it as they see it, Loggains said, so all he can do is tell players to be smart and keep their hands inside the framework. But the official language in the N.F.L. rule book calls even that contact illegal “regardless of whether the blocker’s hands are inside or outside the frame of the defender’s body.”

For Shell, the increased emphasis is frustrating, he said, because it feels as if his position is now being targeted by the officials.

“The defensive guys hold, too, and they don’t ever get called, but we always get called,” he said. “Sometimes you don’t mean to hold, it’s just how your hands are placed and how you have a guy and controlling him, you don’t want to let go.”

The Jets have been flagged 24 times this season, seven for offensive holding. But while running back Le’Veon Bell said he believed the team was hurting itself with penalties this season, he did not see offensive holding as an issue.