Tyson Gay tests positive for banned substance and pulls out of world championship By Ashley Collman and Associated Press American 100-meter record holder Tyson Gay has tested positive for a banned substance and says he will pull out of the world championships next month in Moscow. Gay isn't revealing the substance, but he says he was notified by the U.S. Anti-Doping Agency on Friday that a sample came back positive from an out-of-competition test May 16. Gay says he will have his 'B' sample tested soon. Doped: Gay seemed genuinely surprised that he tested positive, in a tearful conversation with the AP Sunday The 30-year-old Gay fought back sobs in a phone conversation with The Associated Press Sunday, saying: 'I don't have a sabotage story. ... I basically put my trust in someone and was let down. The USADA issued it's own statement in response to the banned substance found in Gay's system: 'In response to Mr. Gay's statements, USADA appreciates his approach to handling this situation and his choice to voluntarily remove himself from competition while the full facts surrounding his test are evaluated. The B sample will be processed shortly, and as in all cases all athletes are innocent unless or until proven otherwise through the established legal process, and any attempt to sensationalize or speculate is a disservice to due process, fair play, and to those who love clean sport. Gay was healthy again this season after being constantly plagued by hamstring and groin ailments, along with a surgically repaired hip. He won the 100 and 200 at nationals last month. Gay set the American record for fastest 100-meter at the Shanghai Golden Grand Prix in September 2009, with a time of 9.69 seconds. At the London Olympics last summer, Gay competed in the fastest ever men's 100-meter race. Let down: At the last summer Olympics, Gay competed in the fastest 100m race in Olympic history, but failed to medal Unfortunately, he just missed the bronze medal in that race by one hundredth of a second to fellow-American Justin Gatlin. Jamaicans Usain Bolt and Yohan Blake placed first and second respectively with 9.63 and 9.80 runs.