Injury ends Roddick bid
World number six Andy Roddick pulled out of the season-ending Masters Cup on Wednesday with an ankle injury.
The 26-year-old American, a three-time title winner this season, suffered the injury during Tuesday's practice following his defeat by British number one Andy Murray on Monday.
World number 27 Radek Stepanek will step in to take the former US Open champion's place in the red group at the eight-man tournament and will face two-time defending champion Roger Federer.
