Tennis-Djokovic says he is unable to travel to New York for U.S. Open

"Good luck to my fellow players! I'll keep in good shape and positive spirit and wait for an opportunity to compete again."

Former tennis world number one Novak Djokovic said on Thursday that he will not be able to travel to New York to compete at the U.S. Open, the last Grand Slam of the year that begins next week.

"Sadly, I will not be able to travel to NY this time for US Open," Djokovic wrote on Twitter. "Good luck to my fellow players! I'll keep in good shape and positive spirit and wait for an opportunity to compete again."