Buenos Aires, Argentina , 11 May 2011 | AP

Former US Open champion Juan Martin del Potro has a left thigh injury that could rule him out of the French Open later this month.

The 22-year-old Del Potro, who won at Flushing Meadow in 2009, has a muscle tear and faces a struggle to be fit in time for Paris when the tournament starts May 17.

“I started the rehabilitation today and I’ll do everything possible to play in Paris,” Del Potro said Tuesday in a statement.

“I want to take things calmly and not rush back to the circuit.”

The injury appears to be a new problem for the 31st-ranked Argentine, who withdrew before a match against Rafael Nadal at the Madrid Open last week because of a hip injury.

Del Potro dropped to No.481 in the rankings in January due to a long layoff after undergoing a wrist operation in 2010.

Subsequent victories in Delray Beach and Estoril, however, suggested he was getting back to his best.