Austria's Bernhard Kohl, the best climber at this year's Tour de France and third overall, is said to have admitted using Cera, the new generation of banned blood booster EPO.
Kohl's reported admission comes 48 hours after he failed a test for the drug in retroactive controls carried out by France's national anti-doping agency.
He joins Italians Riccardo Ricco and Leonardo Piepoli and Germany's Stefan Schumacher as the fourth rider on this year's Tour caught out by the new tests.
In acknowledging his wrongdoing and giving up the right to have his second sample examined, Kohl faces a two-year ban.
