The former U.S. Open champion Juan Martin Del Potro of Argentina has torn a hip muscle, putting his participation in the French Open in doubt.
Del Potro won his first grand slam title at the U.S, Open in 2009, the year after he won in Auckland.
The former world number four has been making a comeback this season after missing almost all of last year following surgery on his right wrist.
He pulled out of the Madrid Masters tournament last week and says tests have shown he's torn a hip muscle.
Del Potro says he's already started rehabilitation and will do all he can to be in Paris.