Fils was poised to take on Roland-Garros 2015 champion Stan Wawrinka, but has now been replaced by Dutch lucky loser Jesper de Jong in the 128-man draw.
“I'm not going to be able to play here this year. It's a shame, of course. I'm very sorry about it,” Fils told reporters on Saturday afternoon.
“In Rome I felt pain around the hip, was bothering me a lot. Then after, I did some examinations. Everything was looking pretty fine, but still a lot of pain.
“I was not able to practice for the last two weeks. Actually, the practice today was my first-ever points since two weeks in Rome.
“I'm not even at 50 percent of my normal shape right now, I will not take any risk like I did last year. I don't want to be stupid.”