Injury blow for Mardy Fish
Mardy Fish's hopes of qualifying for the ATP World Tour Finals later this month took a huge hit after he suffered a hamstring injury at the Swiss Indoors.
The American was forced to retire hurt just 11 minutes into his first-round clash with James Blake in Basle.
The 29-year-old is currently eighth in the race for the season finale in London finale, with the final three places in the elite eight-man field still to be decided.
The line-up for London will be finalised next week, with Fish likely to drop out of the top eight if his injury keeps him out of action.
Fish recently replaced Andy Roddick as the top-ranked American player after a sparkling run of form, winning 20 of his 26 matches since July.
Spaniard Nicolas Almagro is currently ninth in the world rankings, just 500 points behind Fish, while Janko Tipsarevic is a further 65 points adrift.
Novak Djokovic, Rafael Nadal, Andy Murray, Roger Federer and David Ferrer have already booked their places.