The 40-year-old hopes to return to the ATP tour.
Roger Federer has revealed he faces “many months” out of the game as he prepares to undergo further knee surgery.
Die 40-jarige, who missed the Tokyo Olympics with a knee injury after losing in the quarter-finals of Wimbledon said he had opted for another operation.
“I’ll be on crutches for many weeks and also out of the game for many months,” he said in a video on Instagram on Sunday evening.
Federer said: “I just wanted to give you a bit of an update about 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 in Wimbledon and it’s just not the way to go forward.
“Unfortunately for the medium to long term to feel better I will need surgery so I decided to do it.”
The former world number one, who has won a joint-record 20 grand slam titles with Rafael Nadal en Novak Djokovic, admitted he did not know whether he would be able to return to his previous heights, only that his desire to return to the tour remained.
Hy het bygevoeg: “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.
“I am realistic, don’t get me wrong, I know how difficult it is at this age to do another surgery to try it but look, I want to be healthy, I will go through the rehab process.
“I think also with the goal while I’m still active which I think is still going to help while I go through this long period of time – also a big thank you for all of your messages which are going to be coming in, you guys are always incredible to think of me, some of you suffer with me and some of you wish me the best and want to see me back on court so I am doing okay.
“I will update you as I move along with my rehab, I wish you all the best.”