The cyclist's Euskaltel Euskadi team said Sanchez, who won the road cycling event at the 2008 Beijing Olympics, will miss the grueling three-week event because he needs to rest.
The 35-year-old Sanchez finished third overall and first in the climber category at the 2011 Tour, winning the mountainous 12th stage.
Reigning Tour champion Bradley Wiggins recently announced a knee problem would keep him from defending his title.
The Tour runs from June 29 to July 21.