American Jarrell Miller has returned an "adverse finding" in a voluntary drug test ahead of his world heavyweight title fight with Britain's Anthony Joshua, boxing promoter Eddie Hearn said on Wednesday, Euronews reports.
The finding could disrupt Miller's upcoming bout with world champion Joshua scheduled for June 1 in New York.
Hearn, who promotes Joshua, said he had been informed of Miller's positive test by the Voluntary Anti-Doping Association (VADA), which works with athletes in boxing and mixed martial arts.
"We have been informed by VADA that there has been an adverse finding in Jarrell Miller's sample collected on March 20th, 2019," Hearn said on his Twitter account.
"We are working with all relevant parties and will update with more details soon. AJ's preparation continues for June 1st."
ESPN reported http://www.espn.co.uk/boxing/story/_/id/26541088/miller-set-face-joshua-fails-drug-test that Miller had tested positive for the banned substance GW1516, which boosts endurance and helps athletes burn fat, citing three sources familiar with the matter.