Former two-division champion Rafael Marquez needs to have surgery for gallstones, which forced him to withdraw from a May 4 fight against Leo Santa Cruz, Golden Boy Promotions chief executive Richard Schaefer told ESPN.com on Thursday.
The scheduled 10-round junior featherweight bout was supposed to take place at the MGM Grand in Las Vegas as one of the featured bouts on the Floyd Mayweather Jr.-Robert Guerrero Showtime PPV undercard.
Schaefer said Marquez (41-8, 37 KOs), a former junior featherweight and bantamweight world champion, already had signed his contract for the fight before withdrawing on Wednesday.
"He needs gallstone surgery," Schaefer said. "That's what he told (Golden Boy matchmaker) Eric (Gomez)."
Santa Cruz (23-0-1, 13 KOs), who recently relinquished his bantamweight title in order to move up in weight, will remain on the card, Schaefer said.
"We were just told about Marquez, so we are looking now for an opponent for Leo," Schaefer said. "We are looking at different options, but the good news is that Leo Santa Cruz is ready, willing and able to fight anyone. So we will see who the best available opponent is for him and we're happy for Leo to still be fighting on the card."
The 24-year-old Santa Cruz, who was born in Mexico and lives in Southern California, had a breakout year in 2012 during which he went 5-0 in an exceptionally busy schedule for a top fighter. After winning a vacant bantamweight world title by lopsided decision against South Africa's Vusi Malinga in June -- in which the all-action Santa Cruz threw more than 100 punches per round -- he made three defenses: knockouts of Eric Morel of Puerto Rico and Victor Zaleta of Mexico and a lopsided decision against Mexico's Alberto Guevara on Dec. 15.
The 37-year-old Marquez, the younger brother of superstar Juan Manuel Marquez, is best known for his riveting four-fight series with Israel Vazquez. But Marquez is a bit past his prime and coming off a ninth-round knockout loss to countryman Cristian Mijares, a former junior bantamweight titleholder, in October.