The reigning U.S. Open champion will not defend his title this year.
On Friday, the 2016 U.S. Open champion and three-time major winner Stan Wawrinka announced that he will not play for the remainder of the 2017 season, due to a knee injury. In a post on Facebook, Wawrinka said he and his team had to make "a difficult decision to undergo a medical intervention" on his left knee.
The World No. 4 pulled out of the ATP Masters 1000 series tournament in Montreal and the Western and Southern Open in Cincinnati earlier in the week.