Former UFC heavyweight champion Fabricio Werdum could be out of his recently announced headline fight in Russia after a potential doping violation.
In a statement issued on Tuesday, the UFC said that Werdum had has been notified of a potential USADA violation from an out-of-competition sample taken on April 25.
The test came a month after his loss to Alexander Volkov in London.
Commenting on the news, Werdum’s manager Ali Abdel-Aziz said: “The entire UFC staff and I are all working together to solve this problem.”
“I’m very confident it will be OK. … It’s a misunderstanding. Something is off. Fabricio did not take anything illegal.”
The potential doping offence puts Werdum’s fight against Alexey Oleynik, billed as the main event for UFC Moscow on September 15, in jeopardy.
The Russia bout was only announced on Monday.
The Brazilian will be provisionally suspended until the USADA legal process reaches a conclusion.
Any potential ban would come as a blow to Werdum, who had put together a two-fight winning streak prior to his loss against Volkov and had been hoping to earn a shot at the heavyweight title.