World 100 metres champion Torri Edwards was banned for two years on Wednesday after a positive test for the stimulant nikethamide.
Edwards, who had been included in the U.S. team for the Athens Olympics, opening on Friday, has appealed to the Lausanne-based Court of Arbitration for Sport.
"Edwards, 27, was banned for two years from all sanctioned competition beginning in July 18, 2004, and all her competitive results were disqualified from that date," the U.S. Anti-Doping Agency said in a statement.
Edwards, 27, inherited the world title after compatriot Kelli White was also banned for two years after admitting taking a variety of banned drugs. Edwards tested positive at an April meeting in Martinique.
She subsequently qualified for the U.S. team in the 100 and 200 metres and was expected to run on the 4x100 metres relay.
The sprinter contended she was given glucose tablets by her physical therapist who did not know they contained a banned substance.
Her ban opens up a place on the 100 team which will now go to twice-Olympic gold medallist Gail Devers, who finished fourth at the U.S. trials.
Devers, 37, won the gold medal in 1992 and 1996 and has also qualified for the 100 metres hurdles, an event in which she has yet to win an Olympic title although she is a three-times world champion.
Edwards's place on the 200 team will be taken by LaShaunte'a Moore.
