Heavyweight star Alexander Povetkin has tested positive for banned substance Ostarine ahead of his fight against Bermane Stiverne in Russia this weekend.
The Voluntary Anti-Doping Association found Ostarine in a Povetkin sample that was taken in December, according to a press release sent out by the WBC, who were sanctioning the contest as a heavyweight title eliminator.
The WBC were told of the findings on Friday and have since withdrawn their recognition of the contest. At this stage it is unclear whether the fight will still go ahead.
Ostarine has been banned by the World Anti-Doping Agency since 2008 as it "is believed to provide some of the same benefits of traditional anabolic/androgenic steroids, such as testosterone" according to the WBC report.
Povetkin had been due to fight WBC champ Deontay Wilder earlier this year but the bout was aborted after the Russian was found to have traces of meldonium in his system.
Povetkin's weekend opponent, Stiverne, also failed a drug test prior to the fight but he was just fined $75,000 for having dimethyamylamine his system.
Stiverne, himself, is now not keen on the fight taking place: "There’s no reason to fight if the WBC won’t sanction the bout, I’m very disappointed in the actions of Povetkin. I’ve been training for months to be victorious.
"To wake up the day of the fight, have breakfast, take a nap and wake up to find out he tested positive is the worst possible situation.
"I'm headed back home to Las Vegas, hopefully the WBC will install me as the mandatory challenger to face (current WBC Heavyweight World Champion) Deontay Wilder. I want the opportunity to fight for the world title again, that was my whole reason to come to Russia was to earn that opportunity."