The current WBC light welterweight titleholder, Subriel Matias, has reportedly returned a positive test for the prohibited substance Ostarine, according to testing conducted by VADA. This test was administered in advance of his scheduled defense against the number one contender, Dalton Smith, set for January 10, 2026, at the Barclays Center located in Brooklyn, New York. The status of the fight is now uncertain.
Matias’ Test Complicates Scheduled Bout
News of Matias’s adverse finding was reported by Mike Coppinger, who indicated that the sample in question was collected on November 9, 2025. Matias has a period of 10 days in which he may request analysis of his B-sample.
The scheduled contest between Matias and Smith is now in considerable doubt. Based on the eventual findings, Matias could potentially face disciplinary action, including suspension and financial penalties. Furthermore, his WBC title could be vacated, leading to a bout between Dalton Smith and the number two ranked Alberto Puello for the vacant championship.
Possible Contamination Defense
In the event that Matias attributes the positive test to the consumption of contaminated food or supplements containing Ostarine, there is no guarantee that this explanation will result in exoneration. The contamination defense has been used extensively by fighters, and its effectiveness in securing clearance is not assured.
Matias secured the WBC 140-lb title by defeating the then-champion, Puello, via a majority decision over 12 rounds on July 12, 2025, in Queens, New York. Many observers felt that Puello had performed sufficiently well to merit the victory, but the judges ultimately favored Matias with scores of 114-114, 115-113, and 115-113.
This development represents a setback for Matias, who had recently claimed the WBC title. He had previously lost his IBF title in a unanimous decision loss characterized by an unattractive fight against Liam Paro a year prior, on June 15, 2024, in Manati, Puerto Rico.
In that earlier contest, Paro frequently engaged in tactics such as pushing and delivering blows to the back of the head without facing penalties. Despite Matias, a Puerto Rican, fighting on his home turf, the referee did not strictly penalize the Australian Paro for his physical and borderline-illegal maneuvers.
Increased Challenge for Smith
Should Puello (24-1, 10 KOs) become Dalton’s (18-0, 13 KOs) opponent for the WBC light welterweight title, Dalton will confront a significant challenge due to Puello’s elusiveness. Puello also possesses durability and is unlikely to be easily overwhelmed by the isolated, powerful shots that Smith typically uses to secure knockouts. On paper, a fight against Puello presents a greater challenge for the British boxer compared to a matchup against Matias, who tends to engage more directly.
