Contador is a three-time Tour winner Cyclist Alberto Contador, winner of the 2010 Tour de France, has revealed that he has tested positive for a banned substance.
Contador’s press officer said he had tested positive for clenbuterol during a rest on the Tour in July.
In a statement, the spokesman added that the Spanish rider was the victim of “food contamination” and would hold a news conference later on Thursday.
Cycling has struggled with doping allegations for years.
Floyd Landis was stripped of his 2006 Tour title for a positive drugs test.
In the statement, Contador’s press officer said the rider was first made aware of the test on 24 August.
He said Contador would hold a news conference in his home town of Pinto, in Spain, at 1200 local time (1000 GMT).
The cyclist would use the news conference “to give his version of what happened” direct to the public, the spokesman said.
Contador won the world’s most prestigious race in 2010 riding for the Astana team.
Clenbuterol, a stimulant that increases breathing capacity and boosts the flow of oxygen in the bloodstream, is often used to reduce body fat.
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