Stan Wawrinka, the reigning U.S. Open champion, will undergo knee surgery and miss the rest of the 2017 season.
The world No. 4 made the unfortunate announcement on Facebook on Friday.
"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," he wrote. "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. I also want to take this opportunity to thank my fans for sending plenty of messages of support during the last couple of days. I will see you all in 2018!"
On Wednesday, the three-time Grand Slam champion announced that he would miss the upcoming hard-court Masters events in Montreal and Cincinnati.
The news comes a little over a week after Novak Djokovic, who Wawrinka defeated in last year's U.S. Open final, revealed that his injured right elbow would force him to sit out until 2018.
Wawrinka, 32, finishes his abbreviated season with a 26-11 record and one title, the 250-level Geneva Open, which he won in May. He reached the semifinals at the Australian Open and the final in Indian Wells—losing to countryman Roger Federer both times—and, most recently, the final at Roland Garros, where he lost in straight sets to Rafael Nadal.
He ended his season on a three-match losing streak, falling to Feliciano Lopez in London in his first match after the French Open and then dropping his Wimbledon opener to Daniil Medvedev.
World No. 59 Florian Mayer will replace Wawrinka in the U.S. Open main draw.
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