In 2006 Contador and five other members of the Astana-Würth team were barred from competing ion the TdF due to alleged connections with the Operación Puerto doping case. He was cleared and allowed to race, but refused then to undergo a DNA test that would have judged whether or not he had any link to the blood bags that were found in the investigation. The Astana Team (and Contador) were not invited to the 2007 tour duie to suscpisoin of doping.
In September 2010, Contador revealed that a urine sample he had given on 21 July, a rest day in the 2010 Tour de France, had contained traces of clenbuterol. In a test taken the day before his clenbuterol positive sample, was reported to contain plastic residue indicating possible blood doping, but the test is not recognised by the World Anti-Doping Agency, so no charges in relation to this finding were brought.
The Spanish Cycling Federation found him innocent. The UCI and WADA appealled this decision and following an extension requested by Contador’s legal team, the hearing with CAS is scheduled for Aug 1–3, 2011.