Dopingskandal Fuentes
Leipheimer won the 2006 Dauphiné Libéré, having gained the overall lead on the stage to Mont Ventoux. He was considered a contender in the 2006 Tour de France after several favorites, including Ivan Basso and Jan Ullrich, were suspended because of the Operación Puerto doping case: Leipheimer, who had been sixth the previous year, was the highest-placed rider returning. However, his final position was 12th, 18 and a half minutes behind winner Floyd Landis.