World Boxing Council president Mauricio Sulaiman has revealed that Luis Ortiz has failed a drugs test just over a month before his heavyweight title fight with Deontay Wilder.
Ortiz is due to step into the ring to face WBC champion Wilder at the Barclays Center in Brookyln on November 11.
That showdown would appear to be in doubt after Sulaiman confirmed that the unbeaten Cuban has tested positive for a banned substance.
Sulaiman tweeted: "@WBCBoxing has received confirmation from @Vada_Testing that Luis Ortiz has tested positive for a banned substance under #CleanBoxingProgram."
There has been talk of a unification fight between the winner of the eagerly anticipated bout in New York and Anthony Joshua if the Briton beats Kubrat Pulev.
Ortiz, nicknamed King Kong, was suspended after testing positive for Nandrolone in 2014, but returned to extend his perfect record to 27 victories.