Former world tennis number one Roger Federer told Swiss media that he will miss the Australian Open in January and is unlikely to return to competition until mid-2022 as he recovers from multiple knee surgeries.
In another blow, the 40-year-old said he would be "extremely surprised" if he was able to play at Wimbledon, a Grand Slam he has won a record eight times.
The 20-time Grand Slam champion said he would be able to resume running in January and return to training on the court in March or April.
Federer's agent did not immediately respond to a request for comment.
The Swiss star is tied with Rafael Nadal and Novak Djokovic in the race to be the most successful men's singles Grand Slam champion of all time.
But he said the next few months will be ''crucial'' for his recovery.
Federer has not won a Grand Slam since clinching the Australian Open title in 2018 but he said said he is still holding out for a "miracle."