Serena Williams has pulled out of the WTA Western and Southern Open because of an injury, and it could jeopardize her standing as the world's top-ranked player.
Williams, 34, was forced to withdraw from the Cincinnati tournament with a right shoulder injury. She was the defending champion.
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"I'm very disappointed I'm not able to compete, as I was really looking forward to defending my title," Williams said in a statement Monday. "My shoulder inflammation continues to be a challenge, but I am anxious to return to the court as soon as possible."
Sad to announce top seed Serena Williams has withdrawn from 2016 tournament due to a shoulder injury.#CincyTennis pic.twitter.com/4XFgQ3YKrU
— W&S Open (@CincyTennis) August 15, 2016
Williams was visibly bothered by the shoulder injury when she was eliminated from the Olympics in a third-round loss to Ukraine's Elina Svitolina.
Williams' withdrawal endangers her streak of 183 consecutive weeks atop the WTA Tour's rankings — three weeks shy of pulling even with Steffi Graf's record of 186.
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Should Angelique Kerber, fresh off a silver medal in Rio, win the tournament, she would overtake Williams as the world's new No. 1.
Her exit also means both the top ranked man and woman in the world have pulled out after poor Olympic campaigns, with Novak Djokovic also withdrawing from the ATP event.
Williams has been replaced by Misaki Doi of Japan.