LAS VEGAS -- Floyd Mayweather Jr.'s comeback has been postponed because the boxer suffered a rib injury while training.
Golden Boy Promotions said on Sunday that Mayweather's July 18 fight against Juan Manuel Marquez at the MGM Grand in Las Vegas will be rescheduled.
"I am extremely disappointed that this fight has to be postponed," Mayweather (39-0, 25 KOs) said in a statement. "I was training very hard and looking forward to getting back in the ring on July 18."
Marquez (50-4-1, 37 KOs) said in a statement from his training camp in Mexico that he was also disappointed.
"I will remain focused, in shape and ready to fight whenever the fight is rescheduled for," the lightweight champion said.
Details about Mayweather's injury were not immediately available. Phone messages left by The Associated Press with Golden Boy and Mayweather's promoters were not immediately returned on Sunday.
It was not clear how long the pay-per-view fight would be delayed.
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. The former five-division champ was slated to fight a rematch with Oscar De La Hoya but instead abruptly retired last June, turning his attention to show business.
Now, many consider Manny Pacquiao boxing's best pound-for-pound fighter after the charismatic Filipino icon beat De La Hoya and Hatton in fewer rounds than Mayweather.
It is possible that Mayweather and Pacquiao will eventually meet in the ring if Mayweather beats Marquez first.