Sam Stosur's best performance at Indian Wells was a semifinal berth in 2010.
Sam Stosur's best performance at Indian Wells was a semifinal berth in 2010.
Matthew Stockman/Getty Images

Sam Stosur has withdrawn from her quarterfinal against Angelique Kerber at the BNP Paribas Open because of a right calf injury.

Kerber will move into the semifinals against either top-seeded Victoria Azarenka or No. 8 Caroline Wozniacki, who play later on Thursday.

Stosur says she hurt her calf muscle in the last game of a three-set win against Mona Barthel on Tuesday. The Australian didn't practice on Wednesday and iced her leg. Stosur was five minutes into her warm-up on Thursday when she realized she couldn't play.

She says this is only the second time she's pulled out of a match in her career and isn't sure how long she'll be sidelined.

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