LAS VEGAS -- Floyd Mayweather Jr. has damaged cartilage in his ribs and will stop training for his comeback fight until a doctor says he can resume.
Richard Schaefer, chief executive of Golden Boy Promotions, told The Associated Press on Monday that Mayweather has been in tremendous pain since suffering the injury during training on Thursday.
"He tried to work through it. He really did not want to postpone the fight, but it came to the point where he could barely sit," Schaefer said. "He could not train, he could not move and there was really not much of a choice."
Mayweather (39-0, 25 KOs) was scheduled to fight Juan Manuel Marquez (50-4-1, 37 KOs) on July 18 at the MGM Grand in Las Vegas.
Schaefer said both fighters have committed to rescheduling and a September date has been mentioned. But promoters and the fighters won't agree to a date without the OK of doctors.
Mayweather's ribs are not broken, and the former five-division champ plans to see a doctor this week, Schaefer said. He said he did not know exactly how Mayweather damaged his cartilage.
"Right now he cannot go and train, he cannot work out, he cannot run, he cannot hit the heavy bag and the speed bags and jump ropes and all these kinds of things," Schaefer said. "He definitely will need some additional training but again, Floyd is such an amazing athlete -- and really on top of his game -- that I think it will be relatively easy for him to get right back into it."
Cartilage connects the ribs to the sternum, and can tear away after direct blows to the chest, other trauma or particularly violent coughs and sneezes.
Dallas Cowboys quarterback Tony Romo injured his rib cartilage during the team's season-ending game at Philadelphia last year, a disastrous 44-6 loss in which Romo fumbled, was sacked and benched. Coach Wade Phillips said a flare-up of the pain caused Romo to collapse in the shower afterward.
Mayweather and Marquez were scheduled to fight at a catch-weight of about 143 pounds, eight more than Marquez has ever fought and the lightest weight for Mayweather since 2005.
Mayweather hasn't boxed since knocking out Ricky Hatton in December 2007. He was slated to fight a rematch with Oscar De La Hoya but instead abruptly retired last June, while still considered the sport's pound-for-pound king.
Now, many believe Manny Pacquiao holds that title after he beat De La Hoya and Hatton in fewer rounds than Mayweather.
It's possible that Mayweather and Pacquiao will eventually meet in the ring if Mayweather beats Marquez first.
But promoter Bob Arum also wants to set up a Pacquiao-Miguel Cotto fight in November, the earliest Cotto can get back into the ring after the welterweight's win over Joshua Clottey on Saturday.
Cotto won by decision but left Madison Square Garden in New York with a big gash over his left eye that required six stitches.