Swiss tennis star Roger Federer announced Tuesday that he will not play any tournaments for the remainder of the 2016 season, since he needs “extensive rehabilitation” after his knee surgery earlier this year. In a post on his Facebook page, he called it a “very difficult position” that he made after consultations with his doctors and team.

Currently ranked third in the world, Federer has been struggling with injury for much of 2016, starting with a knee surgery in early February, soon after his loss to Novak Djokovic in the semifinal of the Australian Open. He returned to action at the Monte-Carlo Masters in April, but injured his back during practice at the Madrid Open in May and eventually withdrew from the French Open as well, the first time since the 2000 Australian Open that he did not participate in a Grand Slam tournament.

Federer’s back injury goes back to 2008, but the first year he failed to win a single major Grand Slam title was 2013. It was also the year where he suffered his worst defeat in a Grand Slam tournament, crashing out of Wimbledon in the second round, which also sent him out of the world top 10 ranking for the first time since 2003.

Despite being regarded by many as the greatest tennis player of all time for his numerous accomplishments and records, Federer has not won any Grand Slam tournament since 2012, even though he made it to the finals of the Wimbledon in 2014 and 2015, and was the runner-up at the U.S. Open in 2015.

However, he plans to come back next year and play for another few. In his own words: “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.”