Oscar Collazo gave up his WBO minimumweight belt on Monday, November 2. The move scraps his ordered defense against Ryusei Matsumoto right before the purse bid. That creates an undeniable roadblock for a champion who’d openly planned to sweep every 105 pound title.

Miguel Cotto Promotions officially alerted the WBO about the decision, which shut down the San Juan purse bid immediately. Interim titlist Matsumoto (9-0, 4 KOs) steps up as full champion once the sanctioning body makes it official.

Collazo originally captured the strap back in May 2023. He still keeps possession of the WBA Super title plus the Ring Magazine belt at 105 pounds. Still, Matsumoto takes the WBO hardware without having to defeat him inside the ropes.

The physical setback that sidelined Collazo plays a massive role here. He fractured two ribs during camp, knocking him out of an October 10 clash with flyweight titleholder Ricardo Sandoval. Moving up two weight classes for that bout was the plan, with the WBO granting permission to hold his minimumweight strap until the opening bell.

Once that opportunity dissolved, Collazo stated he wanted to stick around at 105 pounds to chase undisputed glory. His stated timetable pointed to a return around January or February 2027.

That timeline makes this sudden vacancy pretty puzzling. Collazo was actively talking up unifications, yet the mandatory defense against Matsumoto vanished completely. He let go of a belt he needed to become undisputed.

His camp hasn’t publicly explained why Collazo surrendered the title rather than pursuing the Matsumoto fight after recovering. His fractured ribs explain the inactivity, but fans are still missing an explanation for why a champion targeting more belts chose to give one up.

The WBO praised Collazo’s reign and said its doors remain open. Matsumoto gets the belt, but loses the chance to take it from Collazo in the ring.

🥊 OFFICIAL WBO ANNOUNCEMENT

Oscar Collazo has formally relinquished his WBO Mini Flyweight World Title, bringing an outstanding championship reign to a close.

Interim champion Ryusei Matsumoto (9-0, 4 KOs) will be elevated to full WBO World Champion status, subject to the corresponding official ruling.

The WBO recognizes Collazo’s remarkable legacy, professionalism, and dedication as a world champion and ambassador for Puerto Rico.

Thank you, Champ!

— WBO (@WorldBoxingOrg) November 2, 2026