John Riel Casimero vs. Guillermo Rigondeaux: Fight prediction, card, odds, start time, how to watch

Casimero will put his WBO bantamweight title on the line in California

John Riel Casimero was set for a huge bantamweight unification clash with Nonito Donaire before it all fell apart. Instead of a bout with Donaire, a fellow Filipino star, Casimero will step into the ring on Saturday to face former world champion Guillermo Rigondeaux (10 p.m. ET, Showtime). John Riel Casimero (c) -230 Guillermo Rigondeaux +190 WBO bantamweight title Gary Antonio Russell -190 Emmanuel Rodriguez +160 WBA interim bantamweight title Rau'shee Warren Damien Vazquez Bantamweight Disputes over drug testing -- with Donaire's side suggesting Casimero balked at Voluntary Anti-Doping Association drug testing protocols, which Casimero denied -- led to Casimero insulting Donaire's wife. As the anger built, Donaire called off the bout entirely. Casimero's consolation prize was a fight with Rigondeaux, which will take place at Dignity Health Sports Park in Carson, California. Losing out on the Donaire fight not only cost Casimero one of the biggest fights possible but landed him against one of the greatest tactical fighters of the modern era. Even at 40 years old, Rigondeaux is a threat to anyone with a crafty and deliberate approach, even if that has produced some less than thrilling outings in the ring.