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.