Federer has withdrawn from this year's French Open after failing to recover from a
back injury.
The 34-year-old did not play in the Madrid Open earlier this month
after hurting his back during practice for the tournament.
"I have been making steady progress, but I am still not 100%," said Federer.
"I feel I might be taking an unnecessary risk by playing in this event before I am really ready.
"This decision was not easy to make, but I took it to ensure I could play the remainder
of the season and help to extend the rest of my career."
It means Federer will miss a Grand Slam for the first time this century.
bbc news 
Roger Federer withdraws from French Open
The 34-year-old did not play in the Madrid Open earlier this month
after hurting his back during practice for the tournament.
"I have been making steady progress, but I am still not 100%," said Federer.
"I feel I might be taking an unnecessary risk by playing in this event before I am really ready.
"This decision was not easy to make, but I took it to ensure I could play the remainder
of the season and help to extend the rest of my career."
It means Federer will miss a Grand Slam for the first time this century.
bbc news