Roger Federer: Former world number one withdraws from French Open
|Venue: Roland Garros, Paris Dates: 22 May to 5 June|
|Coverage: Live radio and text commentary on selected matches on BBC Radio 5 live sports extra, the BBC Sport website and app.|
Roger Federer has withdrawn from this year's French Open after failing to recover from a back injury.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.
Federer returned for the Italian Open but was beaten in the third round by Dominic Thiem.
"I have been making steady progress, but I am still not 100%," said the world number three.
"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.
The Swiss has struggled with injury this year, having undergone knee surgery after January's Australian Open.
The former world number one returned for the Monte Carlo Masters in April and reached the quarter-finals, where he was beaten by Jo-Wilfried Tsonga.
Federer, winner of the 2009 French Open, has played just four events in 2016.
BBC tennis correspondent Russell Fuller
Federer had been practising at Roland Garros this week, but the decision does not come as a surprise. The injury has seriously curtailed his preparations and his focus this year is on Wimbledon and the hard courts of the Rio Olympics and the US Open.
It has been a phenomenally frustrating year for Federer, who has played only four events because of his back, a bout of flu and the knee cartilage he tore when running his twins a bath. He does not normally need many matches to play himself back into form after a break, but he will be 35 in August, and it was a back injury which caused him lengthy problems throughout 2013.
Federer's withdrawal means that Rafael Nadal will become the fourth seed - and therefore would no longer face Novak Djokovic or Andy Murray before the semi-finals.
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