Juan Martin del Potro admits that he is unsure about how successful his latest comeback from injury will be, as he prepares to play at the Delray Beach Open.
The injury-plagued former US Open champion sustained a fracture to his right kneecap at the Shanghai Masters in early October and only now is he ready to see if he is capable of mixing it on the ATP Tour.
Delray Beach is a good time to see how my knee works during a match and then we'll decide where's going to be next.Juan Martin del Potro
The Argentinian told the official ATP Tour website: "After bad days I started believing in my doctors again that I'll play tennis soon and I think I’m in a good way again to be competitive.
"After four months I'm going to be playing a tournament, which is good recovery time.
"I know it takes time and then you have to be having enough confidence to move 100 per cent, to feel the body in good shape and then the tennis part comes.
"First of all I have to be healthy and then I will start to think about tennis. But Delray Beach is a good time to see how my knee works during a match and then we'll decide where's going to be next."
Del Potro, who has been ranked as high as number three in the world, triumphed at Flushing Meadows back in 2009 and made a sensational return to the final of the US Open last year - only to be beaten by Novak Djokovic.
Del Potro is 1/4 to win his comeback match against Yoshihito Nishioka, with the Japanese 11/4 to claim a victory.
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