The lure of having their children coached by an N.F.L. quarterback had attracted parents from around central Texas, and when Smith did not show, some grumbled about it.

“His word is gold,” Hurtado said of Enemkpali. “And I think that’s what hurts him so much. He got played for a punk, for lack of a better word, and on top of that, he looked bad to his community — like he didn’t come through with Geno Smith, like it was his fault.”

It is unclear how often he asked Smith to reimburse him, but the longer Smith went without paying, the more disrespected Enemkpali felt, friends said. It became a joke among some players on the Jets, who would ask Enemkpali if Smith had paid him back yet.

The only details of the fight have come from the Jets’ coach, Todd Bowles, who said that Enemkpali “sucker-punched” Smith. Bowles characterized the spat as “very childish” but, citing a promise he made to both players, did not reveal the cause. No one who witnessed the confrontation has spoken publicly about it.

Lucas said he was told that Smith put his finger in Enemkpali’s face. That is when Enemkpali belted him.

In the days since, Enemkpali has publicly apologized to the Jets and expressed gratitude to the Bills for giving him another chance.

“I look forward to being a good teammate, an accountable player,” he said Thursday, the only time he has addressed the episode in comments to the news media.

Lucas spoke to Enemkpali the day of the fight and said he sounded remorseful.

“He said he wished he could go back to the time of when they were talking,” Lucas said. “I said, ‘You should have smartened up. You had everything to lose, and he had nothing to lose. You should have been the bigger person and just walked away.’ ”