LOS ANGELES (Reuters) - The heavily anticipated rematch between Britain's Amir Khan and Lamont Peterson, scheduled for May 19 in Las Vegas, has been cast in doubt after the American tested positive for a banned substance, organisers said on Tuesday.
Peterson, who beat Khan in controversial circumstances to win the WBA super-lightweight and IBF light-welterweight belts in December, failed a drug test administered by the Las Vegas-based Voluntary Anti-Doping Association in March.
Khan's promoter, Richard Schaefer of Golden Boy Promotions in Los Angeles, said he was told by Nevada Athletic Commission executive Keith Kizer on Monday about the failed test.
"He (Kizer) was informed that Lamont Peterson has tested positive for substances consistent with the administration of a steroid," Schaefer said on a conference call on Tuesday.
"Both the 'A' and 'B' samples showed that the athlete's specimens were consistent with the administration of an anabolic steroid such as testosterone.
"I discussed with Keith Kizer what is next and he informed me that Peterson's attorneys will be submitting paperwork this afternoon to the Nevada Athletic Commission explaining themselves and explaining why there was a substance there."
After Team Peterson has presented its defence, the chairman of the commission will rule on whether or not there will be a fight in Las Vegas on May 19.
Peterson needs to win an appeal to the five-member commission, which is not scheduled to meet again until May 21, though Kizer said that date could be brought forward.
"If they (the commission) felt there was a need to, if there was some legitimate question of fact, they could meet (before) then," Kizer told Reuters.
"My understanding from my brief conversation with his (Peterson's) attorney was that when he was first told in April that he had tested positive for testosterone, he had no clue what it could be but that it had to be a mistake.
"Then the 'B' sample came back on May third positive as well and then at that time, I guess a light bulb went off that he had had some testosterone problems before the first Khan fight."
Kizer said the Nevada Athletic Commission expected to receive the paperwork from Team Peterson before close of business on Tuesday.
"I am eagerly awaiting it," Kizer said. "Unless he has got some really enlightening defence here, he will not be licensed for May 19th."
Meanwhile, Khan continues to prepare for the May 19 fight with his trainer Freddie Roach at the Wild Card Boxing Club in Los Angeles.
"He is very disappointed but he is going to follow whatever the Nevada Athletic Commission is going to rule," Schaefer said.
Khan has been eagerly preparing for the rematch after losing his WBA and IBF belts in Lamont's home city of Washington on a split decision having been docked two points by the referee for pushing.
Khan's camp criticised the referee's actions and were shocked by television replays showing a mystery man in a hat talking with a judge ringside, prompting the WBA to order a rematch.
The 'mystery man' was identified as Mustafa Ameen, who is an IBF volunteer helping cash-strapped boxers. He denied interfering with the judges' scorecards.
Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue