Junior welterweight champion Lamont Peterson fails drug test World junior welterweight champion Lamont Peterson has tested positive for synthetic testosterone, jeopardizing his May 19 title defense against England's Amir Khan at Mandalay Bay in Las Vegas. Keith Kizer, executive director of the Nevada State Athletic Commission, and Richard Schaefer, Peterson's promoter, confirmed Tuesday they've been notified of the positive test by the Voluntary Anti-Doping Assn. Kizer received a letter Tuesday explaining the result from Peterson's attorney. The letter claimed Peterson had legitimate therapeutic reasons for taking the substance. VADA allows athletes to disclose those reasons, but a consultant for the agency said Peterson did not do so. After reviewing the 132-page letter, the Nevada commission is empowered to decide whether to conduct a special meeting or "whether there will be a fight or not," Schaefer said in a Tuesday morning conference call with reporters. World Boxing Assn. and International Boxing Federation champion Peterson (30-1-1, 15 knockouts) defeated Khan (26-2, 18 KOs) in a controversial decision in December in his hometown of Washington, D.C. Peterson has upset Schaefer by not reporting the positive results of his first, A, sample, which was established April 13. Kizer said the second, B, sample also was identified as positive on May 2. Typically, as in the recent case of Ultimate Fighting Championship heavyweight title challenger Alistair Overeem, Nevada's commission will suspend fighters who submit a positive test for performance-enhancing drugs for nine months. Schaefer said if Peterson is suspended, the entire fight card will be scrapped. "We'll follow where the athletic commission stands," Schaefer said. Kizer painted a grim picture for Peterson. Kizer said Peterson's attorney, Jeff Fried, reported that after the B sample came back as positive, Peterson remembered using a product known as testosterone pellets after getting a prescription for the substance from a Las Vegas doctor in November 2011 - using the product before his first Khan fight. Khan's father, Shah, said he would wait for the Nevada commission to rule on Peterson's eligibility, but added, "If [Peterson] used that before the first fight, it should be ruled a no-contest." Kizer said testosterone pellets are typically used by women for menstrual cramping and absorb through the skin under a fatty area, like the underarm.