World heavy weight champion Anthony Joshua’s defence of his world titles is in serious doubt after Jarrell Miller failed a drug test.
Joshua is due to put his IBF, WBA and WBO heavyweight belts on the line against Miller at Madison Square Garden in New York on June 1.
But the American could now face a ban after testing positive for banned GW1516, a substance which increases aerobic power and endurance.
The substance was added to the World Anti-Doping Agency’s banned list in 2009 and reportedly costs up to $1000 for 10g on the black market.