Roger Federer has said he will miss a number of tournaments, including the French Open that begins in May, after undergoing knee surgery in Switzerland on Wednesday.
The 20-times Grand Slam champion had been struggling with injury at the Australian Open, where he made a semi-final exit to eventual champion Novak Djokovic, and has not played since.
Federer, 38, said he would also miss ATP tournaments in Dubai, Indian Wells, Bogota and Miami.
"My right knee has been bothering me for a little while. I hoped it would go away, but after an examination and discussion with my team, I decided to have arthroscopic surgery in Switzerland yesterday," Federer said in a statement on Twitter.
"After the procedure, the doctors confirmed that it was the right thing to have done and are very confident of a full recovery."
The Swiss skipped the entire claycourt season in 2017 and 2018 and last year played only two tournaments on the surface before arriving in Paris for the French Open.
His agent told Reuters last week that Federer was planning on playing only at Roland Garros while skipping the Madrid and Rome Masters.
The French Open begins on May 24.