Sprinter Tyson Gay on Friday was suspended for one year after he tested positive for using a banned substance, and has returned the silver medal that he got in the 400-meter relay at the 2012 Olympics.

The US Anti-Doping Agency said that the one-year suspension began on June 23, which is the same day that Gay's urine sample was collected at the US Championships as reported by the Associated Press.

Part of the penalty is Gay returning the silver medal he received as part of the US team that finished second to the Jamaican squad spearheaded by Usain Bolt at the London Games. During that team relay, the US team seat a national record timing in at 37.94 seconds. Gay has returned his medal to the US Olympic Committee.

In a statement, USADA CEO Travis Tygard commended Tyson's acceptance of the decision: "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."

Gay was among the best in the game in 2007 when he dominated the world championships in Japan, capturing the gold in the 100, 200 and 400 relay. But that was before Bolt emerged to become the fastest man on the planet. Gay has the American record for 100 meters at 9.69 seconds. Bolt has the world record at 9.58 seconds.

Aside from age, Gay has also been dealing with injuries that have led him to slow down, so to speak. He has had hip surgery, strained groins and hamstring tightness.