Rafa Nadal is still unsure if he will recover from a nagging knee problem in time to play in Spain's Davis Cup tennis semi-final against the United States next month.
The world number three hasn't played since suffering a surprise second-round Wimbledon defeat in June.
He missed the Olympic Games, where he was the defending champion, and was forced to withdraw from the U.S. Open suffering from Hoffa's syndrome, a swelling round the tendon just below the kneecap in his left leg.
Spain is chasing its fourth Davis Cup title in five years but Nadal says he simply doesn't know if his knee will be right in time.
Due to his physical style of play, Nadal has suffered a string of injuries during his career, including a foot injury in 2005 and more recently problems with his knees.