Stan Wawrinka will miss the French Open for the first time since 2004 as he continues to recover from injury.
The 2015 champion has not played since losing in the first round of the Qatar Open in March, having undergone a "small procedure" on his left foot shortly after the tournament.
He said at the time he will be out for a few weeks, but he is now set to end a run of 16 consecutive appearances at the French Open, which starts on May 30.
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The 36-year-old has been sharing videos and photos on social media from his base in Monaco as he looks to work his way back to full fitness.
His goal will likely be to return to the ATP Tour during the grass-court season ahead of Wimbledon, which gets under way on June 28.
Andy Murray is in a similar position to Wawrinka as he is also set to miss the French Open.
Murray, who hasn't played a singles tournament since early March, was expected to receive a wildcard for the tournament.
However, the 2016 French Open finalist has decided to instead focus on the grass-court section of the calendar this summer.
Our view - Wawrinka, Murray absences show times are changing
It doesn't seem too long ago that Wawrinka and Murray would have been among the potential contenders at the French Open. Wawrinka in particular looked at home on the clay in Paris as he blazed his way to victory in 2015 and then reached the final two years later. Murray took his time to adjust but made the final in 2016 and three semi-finals either side of that.
The loss of both for this year's tournament shows how times are changing on the ATP Tour.
Wawrinka and Murray have both battled a number of injury issues over the last few years and don't look as though they are going to return to the heights they once hit. Now it's over to the next generation to step up and see if they can make their mark, with the ever-present challenge of Rafael Nadal still standing in the way in Paris.
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Who's playing the 2021 US Open and who is missing?