The 36-year-old former Olympian returned a positive sample after an out-of-competition test conducted by the South African Institute for Drug-Free Sport (SAIDS) in August.
“On 29th August 2012, I returned an out-of-competition positive test for Erythropoietin,” George said in a statement.
“I will not be asking for a B sample to be tested as I know the result will ultimately be the same.”
George, who rode alongside Armstrong in the 1999 and 2000 seasons as part of the U.S. Postal Service team, has been provisionally suspended pending an investigation by an independent tribunal.
American Armstrong was banned for life and stripped of his seven Tour de France titles last month after former team mates testified that he had been involved in what the United States Anti-Doping Agency (USADA) described as “the most sophisticated, professionalized and successful doping program the sport has ever seen”.
