Former Olympic time trial champion Cancellara out of Tour
Switzerland's Fabian Cancellara pictured during the tenth stage of the 101st Tour de France between Mulhouse and La Planche des Belles Filles ski resort, eastern France on July 14, 2014 - by Lionel Bonaventure
The 2008 Beijing Olympic time trial champion said he needed some rest before September's World Championships, at which he will be aiming for a fifth world time trial title.
"I'm going to go home and have a break. It's been a long season," he said.
"I've had 59 days of racing (this year) and I have another big objective at the end of the season with the World Championships.
"It's important that I get some rest."
Cancellara is the third Trek rider to abandon the Tour following 2010 champion Andy Schleck and Dutchman Danny van Poppel.
Apart from being a time trial specialist, Cancellara is also one of the greatest one-day racers of all time.
He has won three of the five Monument races, including Paris-Roubaix and the Tour des Flandres three times each, with one victory in Milan-San Remo.