Roger Federer will miss the US Open and will be out for “many months,” according to him, due to a third operation on his right knee. The surgery will give him “a glimmer of hope” that he will be able to compete again.

Last year, the 40-year-old Swiss—a 20-time Grand Slam winner, underwent two knee surgeries.

Federer stated in an Instagram video that he believed the operation would offer him “a glimmer of hope” for a comeback. In July, he was knocked out of the Wimbledon quarterfinals and so missed the Tokyo Olympics.

Federer, who turned 40 a week ago, stated on Sunday evening, “I’ll be on crutches for many weeks, and also out of the game for many months.”

“It’s going to be difficult 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.” He added, “I also want to give myself a glimmer of hope to return to the tour in some shape or form.”

“I am realistic—I know how difficult it is at this age right now to do another surgery and try it…, but I want to be healthy. I will go through the rehab process with a goal, while I’m still active, which I think is going to help me during this long period of time,” he said, reports the BBC.

Federer, who’s currently ranking 9th in world rankings, told reporters after losing to Hubert Hurkacz of Poland at Wimbledon that he wasn’t sure whether he would return.

In the last two years, he’s had his Grand Slam title total matched twice: first by Rafael Nadal of Spain at the 2020 French Open, and then by Novak Djokovic of Serbia at Wimbledon 2021.

After the Australian Open in 2020, Federer underwent two procedures on his right knee before returning to the Tour in Doha in March.