MASON, Ohio - Roger Federer says he will miss the Western & Southern Open and the rest of the season to protect his surgically repaired left knee.
That could leave the W&S Open without both of its defending champions since Serena Williams hasn't entered the event yet. She is committed to the Rio Olympics the previous week and could skip the Mason event next month.
Federer, seven-time champion in Mason, wrote on his Facebook page Tuesday that he needs "more extensive rehabilitation following my knee surgery earlier this year."
"The doctors advised that if I want to play on the ATP World Tour injury free for another few years, as I intend to do, I must give both my knee and body the proper time to fully recover," Federer said.
That also means missing the Olympics and the U.S. Open.
His agent, Tony Godsick, wrote in an email to The Associated Press that Federer's plan is to "be ready for the start of next year."
Federer is the first member of tennis' so-called "Big 4" — a group that includes Novak Djokovic, Rafael Nadal and Andy Murray — to pull out of the Rio Games, where that sport's competition starts on Aug. 6, a day after the opening ceremony.
The arthroscopic procedure Federer had on his knee in February, repairing torn cartilage, was the first operation of his lengthy and accomplished career. He's also had back issues this season, missed the French Open to end his record 65-appearance streak at major tournaments, and did not win a title of any sort in 2016 — making it the first year since 2000 he will end without at least one trophy.
So after participating in every single Grand Slam tournament from the 2000 Australian Open through the 2016 Australian Open, Federer will be sitting out two of the last three this year.
The owner of a record 17 Grand Slams titles turns 35 on Aug. 8.
He hasn't played since losing to Milos Raonic in the Wimbledon semifinals early this month. Federer fell awkwardly during that match and said at the time he wasn't sure how badly he might have been injured.
In his statement Tuesday, Federer wrote: "The silver lining is that this experience has made me realize how lucky I have been throughout my career with very few injuries."
And he added: "I am as motivated as ever and plan to put all my energy towards coming back strong, healthy and in shape to play attacking tennis in 2017."