World number four Stan Wawrinka announced on 4 August that he will not defend his US Open title and miss the rest of the season after deciding to undergo knee surgery.
The 32-year-old, who was seen struggling with a knee problem during his first-round loss to Daniil Medvedev at the Wimbledon, had earlier withdrawn from the upcoming Canadian Masters in Montreal.
However, he has now decided to end his year early in order to cure the problem completely.
Announcing the news via his official Facebook account, Wawrinka, "I am sad to announce that, after talking with my team and doctor, I had to make a difficult decision to undergo a medical intervention on my knee .This was the only solution to make sure I will be able to compete at the top level for many more years."
"This is obviously extremely disappointing, but I'm already looking ahead and planning my recovery. I love this sport and I will work hard to get back to my top level and play many more years," he added.
Earlier, Serbian maestro Novak Djokovic also called an early end to his season to rest an elbow problem that forced him to retire during his Wimbledon quarter-final against Tomas Berdych, the Guardian reported.
Now, it remains to be season whether world number one Andy Murray, who withdrew from next week's Rogers Cup in Montreal due to a hip problem, will be fit enough in time to compete in Cincinnati the following week or at the US Open.