Paris:Gael Monfils could miss next month's French Open because of a left knee injury.
The Frenchman, who reached the semi-finals at Roland Garros last year, told sports daily L'Equipe on Tuesday that he underwent MRI exams and that the results were "not good." He is set to have further scans in two weeks.
"Frankly, it's really hard to explain. It's something pretty serious and there is a possibility that I will not play at Roland Garros," Monfils was quoted as saying. "But I want to keep hope alive. For the moment I'm rested, the only thing I can do is to wait."
According to French tennis federation doctor Bernard Montalvan, the 10th-ranked Monfils picked up Osgood-Schlatter's disease when he was a teenager, an illness which can cause acute inflammation.
"From time to time, there is an inflammation of the kneecap tendon and it's the case now," Montalvan said.
Monfils was sidelined for three months with the same problem in 2007. The Frenchman, who withdrew from this week's Barcelona Open, will also miss the Rome Masters and Madrid Masters. The French Open starts on May 25.