Maria Sharapova, the 2006 U.S. Open champion, has withdrawn from this year's competition because of bursitis in her right shoulder, according to a statement from tournament director David Brewer. The tennis star's agent has said that Sharapova's shoulder has been bothering her since before the French Open in May. Sharapova's tennis season has been anything but uneventful: she was sidelined after a hip injury during Wimbledon, hired a new coach, then fired him after losing one match last week at the Western & Southern Open in Mason, Ohio.