John Riel Casimero cannot see 2021 end soon enough.

The three-division and (for now) reigning WBO bantamweight titlist has been forced to withdraw from his mandatory defense versus Paul Butler due to late-surfacing medical reason. Casimero reportedly suffered from gastritis, which left him unable to attend the official pre-fight weigh-in ahead of Saturday’s show at Coca-Cola Arena in Dubai.

Butler—a former IBF bantamweight titlist—will remain on the show, facing fellow former 118-pound title claimant Joseph Agbeko. Both boxers made weight on Friday, though it remains unclear if the WBO title will be at stake for their bout. The sanctioning body has yet to make an official ruling on whether Casimero (31-4, 21KOs) will be stripped of the title for failure to go through with his mandatory title defense.

Butler and Agbeko are ranked number-one and number-eight, respectively, in the WBO bantamweight ratings.

Event promoter Probellum confirmed that Casimero—who never left his hotel room ahead of the weigh-in—was removed from the show, though equally cryptic as to the exact stakes for Butler-Agbeko.

Should the belt be declared vacant, it will mark the third time that Casimero will see a title reign outside the ring, and his second such occasion where it comes due to failure to make weight. The 32-year-old from Ormoc, Philippines saw his IBF junior flyweight title reign end at the scales after weighing a beefy 113 ¾ pounds—nearly six pounds above the divisional limit—ahead of an eventual first-round knockout of Mauricio Fuentes in May 2014.

Casimero went on to win the IBF flyweight belt following a fourth-round knockout of long-reigning and then-unbeaten titlist Amnat Ruenroeng in their May 2016 rematch. The sequel came eleven months after their first fight, which saw Casimero suffer a questionable twelve-round, unanimous decision in a foul-filled affair. Just one successful defense came of his reign, a tenth-round knockout of Charlie Edwards—who would go on to win the WBC flyweight belt—before moving up to bantamweight.

The third title reign began with an interim belt which Casimero claimed in a twelfth-round stoppage of Ricardo Espinoza in April 2019. The fight came about due to then-WBO titlist Zolani Tete having been tied up in the World Boxing Super Series bantamweight tournament, though having to withdraw due to injury. Tete eventually made his way to Casimero, who scored a third-round knockout to emphatically launch his full title reign.

Two successful defenses followed, though none before the start of the pandemic. Casimero was initially due to face WBA/IBF champ and pound-for-pound entrant Naoya Inoue (21-0, 18KOs) in a three-belt unification bout last April in Las Vegas. However, the event was shut down due to the global health crisis, leaving Casimero not only without a fight but stranded in Vegas due to travel restrictions.

Casimero made his way back home before returning to the U.S. for the first of two title defense, beginning with a third-round knockout of unbeaten Duke Micah last September. In his most recent start, Casimero earned an ugly points win over two-time Olympic Gold medalist and lineal junior featherweight king Guillermo Rigondeaux this past August 14 at Dignity Health Sports Park in Carson, California.

The bout with Rigondeaux came back around after Casimero saw a planned title unification clash fall through the cracks. Casimero was already due to face Rigondeaux on the date, only to subsequently agree to an all-Filipino title fight showdown with four-division and newly crowned WBC bantamweight champion Nonito Donaire. A breakdown over random drug testing protocol among other issues saw the fight quickly go sideways, leading Casimero to revisit original plans to defend versus Rigondeaux.

Ironically, Casimero subsequently benefited from the out-of-ring assistance from Donaire and his wife/trainer/manager Rachel, who worked with the charismatic figure in securing a place on Saturday’s show in Dubai.

The fight with Butler landed in the hands of Probellum, an upstart promotional outfit founded by Donaire’ promoter Richard Schaefer who won the rights to Casimero-Butler. Schaefer was the lone bidder during an October 7 purse bid hearing, submitting $105,000 for the title fight.

Casimero was due to make $78,750—75 percent—as the defending titlist, though without the services of his main team including estranged manager Sean Gibbons and strength and conditioning coach Angel ‘Memo’ Heredia. has learned that Casimero was struggling to get down to the 118-pound limit, though it remains moot in light of his reported medical diagnosis.

With the fallout, unbeaten IBF flyweight champion Sunny Edwards will advance to the main event in his mandatory title defense versus Philippines’ Jayson Mama. Both boxers weighed 111 ½ pounds for the scheduled 12-round bout, which was originally due to take place in September.

Edwards was forced to postpone after suffering an ankle injury just ahead of fight week. Saturday’s bout will mark the first title defense for Edwards, a supremely gifted boxer from Croydon, London who won the crown following a twelve-round, unanimous decision over two-time titlist Moruti Mhtalane on April 30 at the famed York Hall in East London’s Bethnal Green.

Mama (16-0, 9KOs) enters his first career title fight, which finally comes on his third try.

The 24-year-old Filipino was due to challenge Mhtalane last December in South Africa, only for the event to be canceled at the eleventh hour and leaving Mama inactive since last February. He made his way to the ring this past April 30—fittingly on the same day Edwards dethroned Mhtalane, with his win coming on a separate show thousands of miles away at home in General Santos City, Philippines.

Jake Donovan is a senior writer for Twitter: @JakeNDaBox