Andy Murray joined Stan Wawrinka and Marin Cilic on the Coupe Rogers sidelines on Thursday when he announced that he would not play Montreal next week.
The Scot, who has won the tournament three times—in 2009, 2010 and 2015—will miss the event for a second consecutive year as he continues to recover from a hip injury.
The Masters 1000 event begins on Monday.
With Murray out, Rafael Nadal has a golden opportunity to retake the top spot in the rankings for the first time since June 2014, shortly after he won his ninth French Open.
Nadal (7,456 points) currently trails Murray (7,750) by just 294 points, and will supplant him as world No. 1 if he reaches the semifinals in Canada.
Roger Federer announced earlier this week that he would play Montreal for the first time in six years, and he and Nadal will now be the top two seeds at a Masters event for the first time since Monte Carlo in April 2011.
Montreal next week will be the first time that Rafael Nadal and Roger Federer have been top two seeds at a Masters since Monte Carlo 2011.— Stuart Fraser (@stu_fraser) August 3, 2017
With No. 1 Murray, No. 4 Wawrinka, No. 5 Novak Djokovic and No. 6 Cilic out, Dominic Thiem and Alexander Zverev will round out the top four seeds in Montreal.
Nadal has posted a 46-7 record this season with titles in Monte Carlo, Barcelona, Madrid and Roland Garros. Murray has gone an underwhelming 25-10 and won just one title, in Dubai in early March.
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