“I’ve been doing a lot of checks with the doctors, as well, on my knee, getting all the information as I hurt myself further during the grass-court season and Wimbledon,” the 40-year-old said in an Instagram post Sunday.”Unfortunately, they told me for the medium to long-term, to feel better, I will need surgery, so I decided to do it. I will be on crutches for many weeks and then also out of the game for many months.”Federer, who is tied with Rafael Nadal and Novak Djokovic on 20 career grand slams, was noncommittal about his future in tennis.”I want to be healthy. I want to be running around later, as well, again, and I want to give myself a glimmer of hope, also, to return to the tour in some shape or form,” he added.”I am realistic, don’t get me wrong. I know how difficult it is at this age right now to do another surgery and try it.”READ: Naomi Osaka to donate prize money to Haitian earthquake relief effortsFederer missed more than a year of action after having two operations on his knee after the Australian Open in 2020.He returned for the 2021 French Open but withdrew after his third-round win to protect his knee. Federer then lost in the quarterfinals at Wimbledon in June.After his Wimbledon loss, he withdrew from the Tokyo Olympics after announcing an injury setback with his knee. This year’s US Open is scheduled to start on August 30 and runs through September 12 in New York.