Tennis star Roger Federer, winner of 20 Grand Slam singles titles, will be on the shelf for “many months” as he undergoes surgery on his right knee for the third time. Because of this, Federer will be missing the U.S. Open. “I’ve been doing a lot of checks with the doctors, as well, on my knee, getting all the information as I hurt myself during the grass-court season and Wimbledon,” Federer said in an Instagram video posted Sunday announcing the news. “Unfortunately, they told me for the medium-to-long term, to feel better, I will need surgery,” Federer added that he wants to be healthy but also says he’s realistic. “I know how difficult it is at this age right now to do another surgery.” Federer had his first knee surgery in February 2020 and then another one in June last year.