Photo: Naoki Fukuda

Heavyweight titleholder Deontay Wilder did not board his 8 a.m. flight to Moscow this morning with the growing sense that his fight next Saturday is likely off after Alexander Povetkin failed a pre-fight drug test for the banned substance meldonium.

However, Wilder’s team wants to remain in Sheffield, England, where they have been training until the WBC makes its official decision on whether to go through with the fight in Moscow.

Sources say Wilder’s camp is frustrated with the position that Povetkin has left them in — stay the course on a fight against someone who failed a pre-fight drug test for a performance enhancer or abandon the match, the promise of a $4.5 million payday and a chance to further solidify his standing in the heavyweight division. There is also the risk that Wilder could somehow be stripped of his title if he doesn’t face Povetkin, who is his mandatory.

Wilder (36-0, 35 knockouts) wants to go through with the fight, regarded as the toughest of his career, sources tell RingTV.com. But his team has strove to convey the risks involved and now there is an increasing feeling among everyone that he will not fight.

Wilder, who holds the WBC title, has publicly clamored for the fight with Povetkin and is sensitive to the perception he might appear as if he is backing out if he doesn’t show up next Saturday. The WBC is investigating the situation and plans to announce soon whether it will sanction the fight.

Russian promoter Andrey Ryabinsky, who handles Povetkin, has claimed that Povetkin used the drug in September of last year when it was still permitted and has not taken it since the World Anti-Doping Agency (WADA) put meldonium on its list of banned substances in January.

But RingTV.com has learned that Povetkin (30-1, 22 KOs) passed pre-fight drug tests administered by the Voluntary Anti-Doping Association (VADA) on April 7, 8 and 11 before his “A” sample showed traces of the drug after a positive urine test on April 27, suggesting that he did in fact take meldonium after the drug was banned. Povetkin has apparently not asked for his “B” sample to be tested. Meldonium can by used by athletes to increase blood flow and endurance.