The Japan Boxing Commission revealed late Wednesday that boxer Kazuto Ioka's urine sample, taken on Dec. 31, showed traces of cannabis.
The announcement comes three days before Ioka's rematch against WBA super flyweight champion Joshua Franco of the United States. Their title fight in Tokyo will go ahead as scheduled because the amount of cannabis found was below the World Anti-Doping Agency's detection limit.
"Ioka hasn't taken or used any banned substance," his Shisei Gym said in a statement. "We'll prove his innocence. We wonder why they needed to announce that at this time."
The sample was taken on the day of the previous match between the two boxers, a two-belt unification fight that ended in a 12-round draw with Ioka fighting as WBO super flyweight champion.
The World Boxing Organization ordered Ioka to arrange a mandatory title defense against top-ranked countryman Junto Nakatani, but Ioka chose to vacate his belt in order to face Franco again.
Ioka was previously embroiled in another doping controversy.
In May 2021, a report by a third-party panel's ethics committee found the "A" sample of his urine taken in December 2020 tested positive for cannabis, but the "B" sample, tested at a later date, did not.
The report added that the JBC neglected to follow proper procedures in storing the samples, and Ioka was not punished.