Matsumoto Claims Vacant WBO Strawweight Title
Oscar Collazo relinquished the WBO strawweight belt before a planned bout, elevating Ryusei Matsumoto to full champion.
Updated on Nov. 2, 2026 in Boxing
Puerto Rico's Oscar Collazo vacated the WBO strawweight title hours before a purse bid for a fight with Ryusei Matsumoto. Matsumoto, who won the interim belt by unanimous decision over Russell Silveira in late September, has been elevated to full champion at 105 pounds.
Why it matters
The vacancy follows Collazo's withdrawal from a scheduled fight with Ricardo Sandoval after a rib injury suffered in training, leaving the division's top title in new hands. The change also determines which fighter controls the WBO strawweight title going forward.
Collazo's record stands at 15-0 with 12 knockouts, against Matsumoto's 9-0 with 4 knockouts, and Teiken Promotions had prepared a $501,000 purse bid for the bout. It is not confirmed whether that bid will be accepted or when the fight will take place.
The players
Oscar Collazo
Puerto Rico's unified strawweight champion, who vacated the WBO title after making seven successful defenses since winning it in 2023.
Ryusei Matsumoto
Japanese boxer who was elevated from interim to full WBO strawweight champion after defeating Russell Silveira.
Teiken Promotions
Japanese promotional company that was prepared to bid $501,000 for a fight between Collazo and Matsumoto.
The details
Collazo first won the WBO belt in 2023 with a seventh-round stoppage of Melvin Jerusalem and went on to make seven successful defenses. He relinquished the title after a rib injury forced him out of a planned fight with Ricardo Sandoval, which was later won by Sergio Mendoza via fifth-round TKO.
Timeline
2023: Collazo first wins the WBO strawweight title over Melvin Jerusalem.
June: Collazo wins a flyweight bout over Neider Valdez.
Late September: Matsumoto wins the interim title by unanimous decision over Russell Silveira.
Last month: The scheduled Collazo-Sandoval fight in Chicago is withdrawn.
November 2, 2026: Collazo vacates the WBO belt and Matsumoto is elevated to full champion.
Big Picture
Matsumoto's elevation follows the WBO's standard practice of promoting an interim champion when the full titleholder vacates, a path that has repeatedly reshaped divisional hierarchies in recent years. The move leaves the strawweight division's top belt in the hands of a Japanese fighter whose record is far shorter than the one Collazo held.
Matsumoto's elevation to full champion means the WBO strawweight title now sits with a 9-0 fighter, and any future defense will be negotiated with his camp rather than Collazo's. Fans tracking the division should watch for an announced purse bid or fight date to confirm the next opponent.
The takeaway
A title vacancy can reshape an entire division in a single day, and the WBO's interim-to-full elevation shows how quickly a challenger can inherit a championship. Watch the sanctioning body's announcements for confirmation of Matsumoto's first defense.
Further reading
Follow the latest title changes and fight announcements in Boxing.
