LONDON (AP) ― Andy Murray withdrew from the French Open on Tuesday because of a chronic back injury and will now focus on preparing for the start of the grass-court season next month.

The U.S. Open champion met with specialists this week after being forced to pull out of his second-match against Marcel Granollers of Spain at the Italian Open last Wednesday because of the long-standing complaint.

“It’s a really tough decision and I love playing in Paris, but after seeking medical advice I am not fit to compete,” Murray said in a statement. “Apologies to the organizers and thanks to everyone for the messages of support. Now my complete focus is on getting back on the court as soon as possible.”

The French Open, the second Grand Slam tournament of the year, starts Sunday.

Last week in Rome, Murray took a long injury break early in the second set against Granollers, getting his left thigh and lower back massaged.

He seemed pessimistic about his chances of playing in the French Open, the only major in which he hasn’t reached the final.

“I have an issue with my lower back. It’s been an issue for a while,” Murray said then. “I want to make sure it goes away. It’s been a problem since the end of 2011 but it got bad during last year’s clay season.

“I would be very surprised if I was playing in Paris.”

Murray reached the quarterfinals at the French Open last year, falling to David Ferrer, before going on to lose his first Wimbledon final to Roger Federer. He avenged that defeat against the Swiss star to win Olympic gold, and downed Novak Djovokic at the U.S. Open for his first Grand Slam title later in 2012.

Wimbledon runs from June 24 to July 7 this year.