British heavyweight Lawrence Okolie has failed a Voluntary Anti-Doping Association (VADA) drugs test, five days out from his scheduled bout against Tony Yoka, Queensberry Promotions have confirmed.
Okolie (23-1, 17 KOs) was scheduled to fight Frenchman Yoka (15-3, 12 KOs) in Paris on Saturday but the fight is now in serious doubt.
Frank Warren's Queensberry confirmed the news Tuesday.
"Last night [Monday], the Voluntary Anti-Doping Association (VADA) informed Queensberry that Lawrence Okolie returned an adverse finding following an anti-doping test conducted ahead of the show in Paris this Saturday," a statement said.
"A further update regarding the event will be made in due course."
Former cruiserweight world champion Okolie was looking for a statement victory in Paris against 2016 Olympic gold medallist Yoka.
Following Queensberry's statement, the Brit said in a post on Instagram: "Before anyone starts imagining the worst, following my bicep injury last year, I sustained an elbow injury on the same arm during this camp. I had a treatment on it and now we are here. I truly hope sense prevails.
"I will of course be fully cooperating with all relevant authorities and I'm confident any investigation will clear my name.
"I won't be making any further comment at this time. Thank you for all your support and see you soon."
Both Okolie and Yoka were coming off victories in Nigeria in December. The Brit is the WBC's No. 1 ranked heavyweight contender behind champion Oleksandr Usyk and interim title holder Agit Kabayel.
A win against Yoka could have put him in line for a mandatory title fight later in the year.