Star boxer Ryan Garcia tested positive for the performance-enhancing substance Ostarine the day before and the day of his upset win over Devin Haney last month, per a Voluntary Anti-Doping Association letter sent to all parties Wednesday and obtained by ESPN.
The samples were taken prior to the fight, but the results weren't known until later.
Garcia has 10 days to request that his B-sample be tested. Garcia's A-sample also screened positive for 19-norandrosterone but its presence is unconfirmed at this time.
"Everybody knows that I don't cheat," Garcia said in a video posted on X, formerly Twitter. "... Never taken a steroid ... I don't even know where to get steroids. ... I barely take supplements. Big lies, I beat his ass."
Garcia, 25, floored Haney three times during the majority-decision victory, but that result now stands to be overturned unless the B-sample returns negative, which is rare.
Garcia also missed weight ahead of the fight, registering 143.2 pounds for the WBC 140-pound title fight. Haney remained the junior welterweight champion even in defeat.