The decision by the 36-year-old Swiss, who was stunned in the final of last year's Rogers Cup in Montreal by German Alexander Zverev, comes less than two weeks after his quarter-final loss at Wimbledon.
"I had a fantastic time in Montreal last year and always enjoy playing in front of the Canadian fans, but unfortunately with scheduling being the key to my longevity moving forward, I have regrettably decided to withdraw from Toronto this year," Federer said in a statement issued by organisers.
"I wish the tournament every success and am sorry to miss it."
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The Aug. 4-12 Rogers Cup will include nine of the top 10 players on the ATP World Tour, including world number one and three-time champion Rafael Nadal and Wimbledon champion and four-time winner Novak Djokovic.
(Reporting by Frank Pingue; Editing by Andrew Bolton)
