United States' Michael Phelps, top, celebrates after winning the men's 100-meter butterfly swimming final, with United States' Tyler McGill beside him at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics, London, Friday, Aug. 3, 2012. (AP Photo/Jae C. Hong)
Michael Phelps is back in the U.S. drug-testing program, the strongest sign yet that he's returning for the 2016 Rio Olympics.
The U.S. Anti-Doping Agency says Phelps was among the athletes who underwent doping tests in the third quarter, the period ending Sept. 30. He was tested twice.
That coincides with Phelps' longtime coach, Bob Bowman, telling the AP last month the swimming great had had resumed occasional training at the North Baltimore Aquatic Club. Bowman, however, characterized it more as an effort to get in shape than launch a comeback.
Still, by rejoining the doping program, Phelps has given himself plenty of time to get in peak condition for the next major meet, the 2015 world championships in Russia, an important steppingstone for Rio.