Tour de France winner Floyd Landis has said he will not take part in this year's race, the French Anti-Doping Agency (AFLD) announced on Thursday.
AFLD said they had postponed their disciplinary hearing into Landis scheduled for Thursday after the American promised not to participate in any race in France until the end of 2007.
Race organisers said he tested positive for the male hormone testosterone from a sample taken during his come-from-behind win in the 2006 Tour.
"Mr Landis has asked the AFLD, in a letter read by his lawyer during the hearing, to have the possibility to first defend himself in front of the American disciplinary body (the US Anti-Doping Agency)," AFLD said in a statement.
"He says in this very letter that he promises not to take part in any race in France until the end of 2007, in particular in the 2007 Tour de France.
"The AFLD subsequently decided to postpone the examination of his case to a date that will be set according to the course of the procedure before the US Anti-Doping Agency."
In his letter, of which Reuters obtained a copy, Landis wrote: "Let me assure you that I fully share the goal of preventing illegal doping..."
He added, though, that two disciplinary
"In this case, and in order to avoid any misunderstanding, I agree voluntarily not to participate in any professional or amateur cycling event in France until December 31, 2007, and in particular the Tour de France 2007."
The 31-year-old has also been charged with a doping offence by USADA and will have a separate hearing before it on May 14, his representative Michael Henson said on Wednesday.
Landis, who has denied any wrongdoing, tested positive after an astounding comeback in the last mountain stage of the 2006 Tour in the French Alps, a day after a poor performance appeared to have knocked him out of contention.
If found guilty, Landis faces a two-year suspension from the sport and the possibility of becoming the first Tour winner to be stripped of his title, although the Californian could then take the matter to the Court of Arbitration for Sport (CAS).
His lawyers say the samples were mislabelled by the French laboratory which conducted the tests, the testing process was unreliable and the rider never in fact tested positive.
Testosterone can speed up recovery after exercise and generally improves stamina and strength.