Maria Sharapova has pulled out of the Beijing Olympics because of a shoulder injury, her official website said on Friday, depriving the Games of one of its biggest stars.

The Russian withdrew from the WTA Rogers Cup in Montreal on Wednesday after a marathon second-round win over Marta Domachowska, and a scan revealed two small tears in her right shoulder.

"I'm packing up real quick to hop on a plane to New York for a second opinion but I wanted to let you all know first that there is no chance of me competing in Beijing," she said on the website.

"The timing is so unfortunate and this makes me more sad than anything."