Novak Djokovic will aim to forget his London Olympic semi-final loss by defending his title at the ATP Tour's Toronto Masters tournament which begins on Monday.
Playing the event means a tight turnaround including a flight from London and an immediate adjustment from the grass of the Summer Games at Wimbledon to the punishing cement of North America.
Djokovic lost in his bid for the Olympic glory when he went down to eventual Olympic gold medal winner Andy Murray 7-5, 7-5 on Friday.
Murray won the 2009-2010 editions in Canada, the first major ATP competition which brings out the world's elite as they prepare for the US Open in three weeks.
Swiss world number one Federer and number three Rafael Nadal are two of the top names missing the tournament. Federer withdrew to concentrate on his Olympic final while Nadal has yet to recover from his chronic knee tendinitis which has left his summer a shambles.
The Spanish clay court king is hoping to return in a week for the Cincinnati Masters in the US, but there are no guarantees about his actual plans or fitness.
Due to the special scheduling circumstances surrounding this year's edition, all 16 seeds in the Toronto draw have byes into the second round.
Djokovic could start in the second round against either Australia's Bernard Tomic or a qualifier; Murray could play one of two qualifiers.
France's Jo-Wilfried Tsonga takes the third seeding while Czech Tomas Berdych, a first-round Olympic victim, stands on fourth ahead of Serb Janko Tipsarevic.
The post-Olympic absences allowed Canadian Milos Raonic into the 16th seeding at home, with the home crowd favourite playing to start against the winner from Alex Bogomolov and Viktor Troicki.