Olympic sprinter Tyson Gay received a reduced one-year suspension for testing positive for a banned anabolic steroid last year, the U.S. Anti-Doping Agency announced Friday. Gay, 31, a four-time U.S. champion in the 100 meters, has returned his silver medal in the men's 4x100-meter relay from the 2012 London Olympic Games. Gay had no comment on the matter, a representative for the sprinter said Friday. He removed himself from the 2013 world championships after testing positive and has not competed since. His one-year period of eligibility began June 23, 2013, the day his sample was collected at the USA Outdoor Track and Field Championships. The urine samples were collected in two out-of-competition tests and one in competition, according to USADA. Since all three samples were tested in short succession prior to notification of the first positive result, the three adverse analytical findings were treated as one offense. USADA said Gay agreed to assist in an investigation into the circumstances of his first positive test on the day he was notified of the result. Because of his cooperation, he was eligible for a reduction of the normal two-year sanction. "We appreciate Tyson doing the right thing by immediately withdrawing from competition once he was notified, accepting responsibility for his decisions, and fully and truthfully cooperating with us in our ongoing investigation into the circumstances surrounding his case," said USADA CEO Travis T. Tygart. He was disqualified from all results from July 15, 2012, the day he first used a product that contained the prohibited substance, USADA said. "USA Track & Field is gravely disappointed any time an athlete uses performance-enhancing drugs, and Tyson Gay's case serves as a lesson about the consequences of making poor decisions," USATF CEO Max Siegel said in a statement. "We appreciate that Tyson accepted responsibility and has assisted USADA by providing information to help battle the use of PEDs." Gay was once part of the U.S. Anti-Doping Agency's "My Victory" program promoting efforts to compete cleanly. After testing positive for a banned substance he became part of a very different campaign. Gay gave an explanation for the positive test last year. "I don't have a sabotage story," he said, according to the Associated Press. "I don't have any lies. I don't have anything to say to make this seem like it was a mistake or it was on USADA's hands, someone playing games. I don't have any of those stories. I basically put my trust in someone and I was let down." His coach Lance Brauman told USA TODAY Sports last year that the person Gay trusted had "no affiliation with me or anyone else in my training group." Healthy for the first time in five years, Gay was having a strong 2013 season until he tested positive. Last season he won gold medals with a time of 9.75 seconds at the U.S. championships in Des Moines. Gay also claimed the 200 title at nationals, winning in 19.74 seconds. The former University of Arkansas sprinter was once a challenger to Usain Bolt, beating him in 2010 in a 100-meter race in Stockholm. Gay has struggled with injuries the past few years, coming back from hip surgery to finish second in the 100 at the 2012 U.S. Olympic trials in 9.86.