New York Jets quarterback Geno Smith has been ruled out for up to 10 weeks after having his jaw broken by a punch from teammate Ikemefuna Enemkpali.
The incident occurred in the Jets' locker room during their training camp as the pair argued over a $600 (£385) debt that the 24-year owed to Enemkpali.
The disagreement boiled over into a brawl and Smith suffered a broken jaw after being punched by the linebacker, resulting in him being ruled out for the start of the campaign.
Meanwhile, Enemkpali was released by the team after head coach Todd Bowles found out about the incident.
He told reporters: "He got cold-cocked, sucker-punched, whatever you want to call it, in the jaw. He has a broken jaw, fractured jaw, it requires some surgery. It's something you don't tolerate. You can't tolerate that.
"If you have a team and you have a bunch of side issues, you can't tolerate that and this is something that happens in the locker room.We're dealing with it internally and that's where we're at right now.
When asked what started the incident, he added: "It's something very childish, something that sixth-graders could have talked about.
"It had no reason happening and if they want to tell you what happened, they can tell you what happened, but I told them I wouldn't say anything about it, so I'll keep it there. I can talk to you guys after practice because I have meetings and then practice."
Ryan Fitzpatrick is now in line to start the season as the Jets' starting quarterback.
