Andy Murray retired from his second-round match with Spanish opponent Marcel Granollers in the second round of the Italian Open on Wednesday with lower back pain and listed himself as doubtful for the French Open.
Murray, who was celebrating his 26th birthday, walked off the court after winning the second set.
''I have an issue with my lower back,'' Murray said. ''It's been an issue for a while.''
Murray took a long injury break early in the second set, getting his left thigh and lower back massaged.
Granollers won the first set 6-3 and Murray won the second 7-6 (5).
This tournament is a key warm-up for the French Open, the year's second Grand Slam, which starts on May 26.
''I would be very surprised if I was playing in Paris,'' Murray said. ''I need to make a plan as to what I do. I'll chat with the guys tonight and make a plan for the next few days then make a decision on Paris after the next five days.
''I want to make sure it goes away,'' Murray added. ''It's been a problem since the end of 2011 but it got bad during last year's clay season.''
Murray called for the trainer while trailing 2-1 in the second set. He then lost the next two games to trail 4-1 before battling back to force a tiebreaker.
''He is a good player and he can do well in Roland Garros and if he has a problem then I can understand he is thinking of Paris,'' Granollers said. ''I think he played better at the end of the second set but he knows his problem.''
The match was played in difficult conditions, with rain drops falling at one point then wind whipping the clay up into the air and players' eyes at other points as the sun also went in and out.
While he is ranked second this week, Murray is seeded third in this tournament.
At last week's Madrid Open, Murray was beaten by Tomas Berdych in the quarterfinals.
Murray's best result in Rome was reaching the semifinals two years ago, when he lost to Novak Djokovic in a third-set tiebreaker.
Rising Polish player Jerzy Janowicz upset eighth-seeded Jo-Wilfried Tsonga 6-4, 7-6 (5) in the second round of the Italian Open on Wednesday.
The 22-year-old Janowicz improved his record against top-10 opponents to 3-5, having closed last year by reaching the Paris Masters final as a qualifier, beating Andy Murray and Janko Tipsarevic along the way. The 24th-ranked Janowicz is one of only five players under the age of 24 in the top 40.
After beating Tsonga with a forehand passing shot up the line on match point, Janowicz celebrated by ripping his shirt apart.
Last week's Madrid Open runner-up Stanislas Wawrinka withdrew before his match against Alexander Dologopolov with a right leg injury.
Later, Rafael Nadal begins his bid for a seventh Rome title against Fabio Fognini of Italy.