Shanghai - Andy Roddick withdrew from the Masters Cup shortly before his match on Wednesday, citing a right ankle injury he suffered during training the day before.
The American, who lost his opening match to Andy Murray, will be replaced in the Red group by Czech Radek Stepanek.
The American dropped his bombshell a few hours before he was due to take to the court against Roger Federer.
"In practise I just went over on it, we tried as much as we could to get it better," he said. "I can't really stop and start very quickly. It's anything when I go kind of over on the outside it hurts.
Shanghai - Juan Del Potro didn't allow his mind to stray to the upcoming Davis Cup final as he handed Frenchman Jo-Wilfried Tsonga a 7-6 (7-4), 7-6 (7-5) Gold group defeat at the Masters Cup on Tuesday.
Shanghai - Juan Del Potro kept his hopes alive for an extended stay at the M
Shanghai - Roger Federer went through what has become his annual sponsor obligation as he taught a group of Chinese teenagers how to shave at a public relations event as the countdown continued on Friday to the Masters Cup.
