Del Potro unable to defend U.S. Open title?

BUENOS AIRES, Argentina (AP) -Defending U.S. Open champion Juan Martin del Potro, who is on the provisional entry list for the Grand Slam this year, has yet to pick up a racket after wrist surgery and the start of the tournament just over five weeks away.

Del Potro said Saturday on his Twitter page that he "continues getting better" but said he could not set a date for his return.

"I still haven't picked up a racket," he said. "This is why I can't set an exact date."

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The United States Tennis Association said in a statement on Thursday that Del Potro was "expected to return to Grand Slam competition."

The Argentine has been sidelined since January with a right wrist injury that required surgery.

Del Potro's kinesiologist also put the Argentine's U.S. Open return in doubt.

"Nothing is sure," Diego Rivas said. "The goal is to return in Bangkok."

The Thailand Open begins on Sept. 27.

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