While the return of the Mallorcan to the summit would be an incredible turnaround, the French Open champion is refusing to get carried away as he seeks a fourth Rogers Cup title.
"I don't even think about that now. I'm trying to have the right preparation now and that's it," Nadal told the ATP's website.
"I'm going to keep trying to play the way I did in the first part of the season, so if I'm able to make that happen, I hope to have a chance to do well," said Nadal, who is preparing for his first action since losing an epic contest to Gilles Muller in the fourth round of Wimbledon.
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Fifteen-times grand slam champion Nadal has spent a career total of 141 weeks as world number one -- seventh on the list.
Murray, who is missing from Montreal as he treats a hip problem, has been ranked number one since last November having claimed five successive titles.
Nadal opens in Montreal against either Croatia's Borna Coric or Russian Mikhail Youzhny.
Second seed Roger Federer also returns to action in Montreal having won his eighth Wimbledon title last month.
The 35-year-old Swiss is also challenging to return to the world number one spot he has occupied for a record total of 302 weeks during his career.
(Reporting by Martyn Herman; Editing by Gareth Jones)
