The Scot, who turned 26 yesterday, was dogged by back spasms in 2012 and walked off court in Italy following treatment for a similar complaint yesterday, after he had won a second set tie-break to square the match.
Play is scheduled to begin at Roland Garros on Sunday 26 May, but Murray fears he is set to miss a grand slam for the first time since sitting out the 2007 Wimbledon championships with a wrist injury.
“I’d be very surprised if I was playing in Paris,” he said. “I have an issue with my lower back that I will try and get sorted in the coming weeks. I think the shots that hurt get exaggerated more on clay.
“I’ll make a decision on Paris after the next five days. I’ll obviously need to take some days off and see how it settles down.”