By Gabriel F. Cordero
According to medical tests, Mexican two-division world champion Rafael Marquez is suffering from gallstones. Marquez was scheduled to fight IBF bantamweight world champion Leo Santa Cruz on the May 4 Mayweather-Guerrero undercard. A source told Fightnews.com that Marquez has signed a promotional contract with Golden Boy Promotions. He was planning to train for the Santa Cruz fight at the Romanza Gym in Mexico City after reuniting with Hall of Fame trainer Nacho Beristain, with whom he had spent his entire boxing career except for his last five fights.