Olympic gold medalist Tyler Hamilton (search) was suspended Monday from competitive cycling for two years for a blood-doping violation discovered at a race in September.

The suspension was handed down by the independent American Arbitration Association-North American Court of Arbitration for Sport (search).

He can return to competition April 17, 2007, but he forfeits all competitive results since Sept. 11, 2004, the day of the positive test at the Spanish Vuelta (search).

The test occurred after Hamilton won the time trial at the Athens Olympics, and his finish there is not affected by the suspension.

Hamilton, who has denied doping allegations, did not immediately return a call for comment. On his Web site Monday, posted before the suspension was announced, he wrote, "I would never risk my health or my wife's health for the sake of racing."

The arbitration panel ruled that Hamilton's positive sample was from a transfusion of another person's blood. That would increase Hamilton's red-blood-cell count, increasing his endurance, U.S. Anti-Doping Agency said.

Based on blood tests done in early 2004, cycling's international governing body, Union Cycliste International, had warned Hamilton and his Phonak team that he was under suspicion.

"UCI took the necessary action to protect the integrity of its sport," said Terry Madden, USADA's chief executive officer. "This decision shows that sport is committed to protecting the rights of all clean athletes and that no athlete is above the rules."