After the retirement of then seven-time winner Lance Armstrong, the main contenders for the overall win were expected to be Ivan Basso from , the 2005 runner-up; and Jan Ullrich from , the third man on the podium in 2005, winner in 1997, and the only previous winner still racing.
Francisco Mancebo of the French team , who finished fourth last year and sixth the year before, was also suspended by his team, and subsequently announced his retirement.