LONDON: Gaël Monfils has admitted he is doubtful for next month's French Open because of a knee condition. The 22-year-old suffers with Osgood-Schlatter's disease and has been hit by a flare-up of the problem. 'It is possible that I will not play Roland Garros,' said the world No10, who reached the French Open semi-finals last year. French federation doctor Bernard Montalvan said: 'From time to time, there is an inflammation of the kneecap and it's the case now.' Monfils, 22, will also miss the Rome and Madrid Masters tournaments.