US sprint star Tyson Gay has received a one-year doping ban from the US Anti-Doping Association (USADA) and returned a 2012 London Olympics silver medal to the US Olympic Committee.

USADA announced on Friday that the 31-year-old American track star tested positive for a banned anabolic steroid in two random out-of-competition tests and one event doping test in urine samples taken by both USADA and the world governing body IAAF.

Gay accepted a one-year period of ineligibility that began on June 23 last year, the day his sample was collected at the US Outdoor Track and Field Championships.

Because the random test positives were collected near the date of the meet, they were treated as one violation.

Gay accepted a one-year doping ban and the disqualification of all results dating to July 15, 2012 – the date he first used a product that contained a banned substance – and forfeited all prizes obtained from that date, which included voiding his effort on the US Olympic men’s 4x100m relay runner-up squad.

USADA said Gay has already handed over his silver medal to USOC officials.

After learning of his violation, Gay removed himself from all competition ahead of last year’s World Championships and has not competed since.

He also agreed to assist USADA in investigating the circumstances behind his positive test, providing assistance and all products he was using at the time he tested positive.

“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,” USADA chief executive Travis T. Tygart said.

Providing assistance allowed Gay to receive up to a 75 per cent reduction in the usual two-year ban under USADA regulations, setting the stage for the imposing of a one-year ban.

That suspension length is subject to appeal by the IAAF and the World Anti-Doping Agency (WADA).