World number two Roger Federer has withdrawn from next month's Rogers Cup in Montreal, though he gave no reason for his decision in a statement released by organisers on Wednesday.
Federer, a 17-times grand slam singles champion, has twice won the elite ATP World Tour Masters event -- in Toronto in 2004 and 2006.
"I am disappointed that I won't be playing in Montreal because it's a tournament and a city that I really enjoy and has incredible fans," Federer, 33, said.
"My family and I have always received first-class treatment from tournament director, Eugene Lapierre, and his team and I hope to be back in the future."
Federer, who lost to Serbian world number one Novak Djokovic in the Wimbledon final earlier this month, will be preparing over the coming weeks for the Aug. 31-Sept. 13 U.S. Open, the year's final grand slam, in New York.
Jerzy Janowicz of Poland will take Federer's place in the main draw for the Aug. 10-16 Rogers Cup.