Zurich, Swiss tennis legend Roger Federer has announced on Instagram that he will miss the US Open, beginning August 30, and "many months" after undergoing knee surgery.

"I just wanted to give you a bit of an update [on] what's been going on since Wimbledon. As you can imagine, it's not been simple. 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," Federer said in a video posted late on Sunday, which was also put up on atptour.com.

"That's just not the way to go forward, so unfortunately they told me for the medium to long term to feel better, I will need surgery. I decided to do it," said the winner of 20 Grand Slam titles.

"I'll be on crutches for many weeks and also out of the game for many months, so it's going to be difficult of course in some ways, but at the same time I know it's the right thing to do because 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 to return to the tour in some shape or form."

The Swiss star, who turned 40 on August 8, underwent arthroscopic right knee surgeries in February 2020 and May 2020. Federer has played five tournaments since having those surgeries, all of which came this season. The 103-time tour-level titlist most recently competed at Wimbledon.

"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," Federer said. "But I want to be healthy, I will go through the rehab process I think also with a goal while I'm still active, which I think is going to help me during this long period of time."

"Also a big thank you already now for all of your (fan) messages that are going to be coming in because you guys are always incredible. You always think of me. Some of you suffer with me," Federer said. "I'll update you as I move along with my rehab. I wish you all the best and I'll check in with you soon."