ESPN, citing multiple unnamed sources with knowledge of the test results, reported Friday that Fury was flagged for the illegal drug during a Voluntary Anti-Doping Association test.

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Fury, 28, was declared “medically unfit” to fight Wladimir Klitschko on Oct. 29 by the event’s promoters. Fury took Klitschko’s title last year in a unanimous decision.

Fury holds the WBA (Unified), WBO, IBO,Ring magazine, and lineal heavyweight titles. He is 25-0 with 18 knockouts.

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American heavyweight Deontay Wilder (37-0, 36 KOs) is the WBC champion and has traded words with Fury in the past. He took some glee in his outside-the-ring rival’s pain.

Fury vs. Wilder is the fight heavyweight fans want to see. This setback makes that even less likely to be coming soon.