John Riel Casimero
Exclusive: John Riel Casimero 'made some bad decisions in his career' says former advisor
The pair were set to meet in December only for Casimero to pull out of the fight with viral gastritis - something Butler believed was a cover-up for not being able to make the 118lb weight limit.
The bout was then rescheduled for April 23 but Casimero was blocked from fighting the Englishman for violating BBBofC rules. The Filipino violated safety guidelines for cutting weight in a sauna.
Casimero has now been demoted to number one in the WBO rankings with Butler - who beat Jonas Sultan last month - elevated from interim titleholder to world champion.
He is now a two-time world titlist, although it has not gone down well with Casimero and his manager Egis Klimas.
"This is insane and completely BS, someone here has to put dirty hands on this. First time I am ever seeing fighter being stripped because of using sauna. What's next???," tweeted Klimas, who also looks after Vasiliy Lomachenko.
Casimero also branded it 'insane' and 'unfair' and his former advisor Sean Gibbons - the president of MP Promotions - said 'health and safety of boxing must come first'.
The 32-year-old is a three-division world champion and is on a seven-fight winning streak. His wins include Guillermo Rigondeaux and Zolani Tete but he has not been in the ring since August 2021.
"It is a shame that a great champion like John Riel Casimero made some bad decisions in his career and with his training for his last two fights," Gibbons told Planet Sport about him being stripped of his world title.
"But we all have to live with our decisions and bad advice we take from unqualified people. John Riel broke the rules and that cost him his world title. The health and safety of the boxing must come first."
Gibbons split from Casimero last year after the boxer opted to go back to the Philippines to train rather than remain in America.
He ignored messages and phone calls from Gibbons before severing ties with mentor Noynoy Neri and strength and conditioning coach Memo Heredia. He replaced the pair with his brother Jayson (as head trainer) and Stephen Lunas.
In December, Gibbons spoke to Spin.ph and said he was open to working with Casimero again in the future.
"The relationship is open to be fixed," said Gibbons.
"We did nothing wrong and welcome Mr. Casimero to come back. Mr. Casimero received really bad advice from his ignorant brother Jayson, and adviser Stephen Lunas."
Re: John Riel Casimero
Paul Butler promoted to full champion status after Casimero stripped of belt
Liverpool's Paul Butler has been elevated to WBO bantamweight world champion with John Riel Casimero stripped of the belt.
Butler, 33, was interim champion after beating Jonas Sultan last month, but has been promoted after Casimero failed to defend his title.
Philippines' Casimero was twice set to face Butler in the ring.
However a December date was postponed after he fell ill, while an April fight fell foul of Casimero's use of a sauna.
The 32-year-old used a sauna to shed weight before a proposed meeting with Butler in Liverpool, contrary to British Boxing Board of Control rules.
However his team had claimed they were unaware of the ban on sauna use, which is a common practice for fighters to make weight elsewhere in the world.
According to the World Boxing Organisation, British Boxing Board of Control officials' checks revealed Casimero had dropped 10lbs in three days in the build-up to the fight.
The WBO said Casimero had been warned that, after failing to make a mandatory title defence in nearly two and a half years, he would be stripped of the title if he was "unavailable to participate, fight, or engage for any reason whatsoever".
Butler, who has 34 wins from 36 fights, and Casimero could still meet however with the latter now installed as number one contender for the belt.
Butler becomes a two-time world champion having also had a stint as the IBF title-holder in 2014.