SHANGHAI, China —  Andy Roddick has withdrawn from the Masters Cup ahead of his Red Group match against defending champion Roger Federer.

An International Tennis Federation official said Roddick had pulled out of the season-ending tournament but did not give a reason. Roddick was to hold a news conference later Wednesday.

Roddick, seeded fifth in the eight-man draw, lost his opening match in round robin play to Britain's Andy Murray.

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