John Riel Casimero’s promoter suggested Wednesday that Nonito Donaire “had ulterior motives” for withdrawing from his bantamweight championship unification fight against his fellow Filipino.

Sean Gibbons, president of Manny Pacquiao Promotions, stated during a virtual press conference to promote the Casimero-Guillermo Rigondeaux fight that Donaire might’ve had second thoughts about boxing the hard-hitting Casimero. Donaire withdrew from what was an intriguing showdown with Casimero late last month, barely a week after a deal was put together, because Donaire and his wife/manager, Rachel, contended that Casimero wasn’t actively enrolled in the Voluntary Anti-Doping Association’s testing program for performance-enhancing drugs.

Noninto Donaire also cited Gibbons’ disrespectful comments directed at his wife on social media as another reason for pulling out of the Casimero match.

Casimero initially was scheduled to fight Rigondeaux, but the Cuban southpaw stepped aside to allow a 118-pound title unification bout between Donaire (41-6, 27 KOs), the WBC champ, and Casimero (30-4, 21 KOs), the WBO champ, because Rigondeaux was led to believe he’d fight the Donaire-Casimero winner in the following fight. The 40-year-old Rigondeaux (20-1, 13 KOs, 1 NC) owns the WBA’s secondary championship within the 118-pound division.

Once Donaire withdrew, Rigondeaux replaced him in what will be the main event of a “Showtime Championship Boxing” tripleheader August 14 at Dignity Health Sports Park in Carson, California.

“Let’s clear up something very quickly,” Gibbons said. “John Riel Casimero never said anything about drug testing. Rachel Donaire put out a narrative that we weren’t signing up with VADA. We received our papers on a Friday [June 25], we returned them on a Saturday [June 26]. This is a clean fighter, always been a clean fighter, been in the WBC program, always available 24/7. So, for them to insinuate all of that, maybe they had ulterior motives. Maybe, all of a sudden, they had like when you buy something and you really don’t want it. They had buyer’s remorse with fighting Casimero.

“So, Casimero’s always been focused on Rigondeaux. That’s who we were fighting first. We’re very happy that Mr. Rigondeaux has got big balls, big cajones, no backing out when there’s a little trash talk. Trash talk’s part of the sport. So, Casimero just always trains. It doesn’t matter Rigondeaux, Donaire, [Naoya] Inoue. He trains to fight, to be ready, and whatever’s in front of him, he’s prepared. So, it doesn’t bother him.”

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.