Cardoso was immediately suspended by his team on Tuesday after the sport's world governing body the UCI said the 32-year-old had tested positive for EPO in an out of competition test.

It means 40-year-old Zubeldia will get the opportunity to compete in his 16th Tour, in support of Contador's bid for a third victory.

Zubeldia is a specialist climber who finished 16th last year and has achieved top 10 finishes on five occasions, including a best of 4th in 2007.

Cardoso, also a climber who was due to compete in his first Tour after twice securing top 20 finishes at both the Giro d'Italia and Vuelta a Espana, tested positive for the banned blood booster on June 18th.

"It is with deep disappointment that we have just learned that our rider, Andre Cardoso, has tested positive for a prohibited substance," Trek said in a statement.

"In accordance with our zero tolerance policy, he has been suspended immediately."