Stan Wawrinka will not defend his US Open title after announcing he will miss the rest of the 2017 season in order to fully recover from a long-term knee injury.

Wawrinka, 32, has been affected by an issue with his left knee in recent months and will undergo surgery in order to cure the problem completely. The world number four confirmed that he would not compete in the two upcoming Masters tournaments earlier this week but revealed on Friday (4 August) that his absence is set to be longer than first thought.

"After sitting together with my team and considering all options, I have made the very difficult decision to end my 2017 season as I need to undergo medical intervention on my knee," Wawrinka was quoted as saying by the ATP World Tour website.

"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 for many more years.

"I also want to take this opportunity to thank my fans who have sent plenty of messages of support during the past few days."

Three-time grand slam winner Wawrinka is the current US Open champion but will not defend his crown at Flushing Meadows this month and has been replaced in the draw by Germany's Florian Mayer.

The Swiss joins Novak Djokovic, the man he defeated in New York last year, on the sidelines. The world number five is currently suffering from an elbow injury which forced his withdrawal from the Wimbledon quarter-finals and will also miss the rest of the season. The illustrious pair may not be the only stellar names to miss the US Open, with world number one Andy Murray still struggling with a nagging hip problem.