London  - Andy Roddick can rest his knee injury from Shanghai without stress after qualifying Tuesday for the sixth spot in next month's ATP World Tour Finals.

The American could well not play again until the November 22 start in London of the eight-man event after learning of his good fortune.

Roddick limped out of last week's Shanghai Masters - an event where nine men retired - fearful of a knee problem. Upon his return home to Texas, doctors prescribed rest.

The American joins Roger Federer, Rafael Nadal, Novak Djokovic, Andy Murray and Juan Del Potro in the year-end field.

Roddick has now earned a berth at the season finale for seven straight years - the second-longest active streak behind number one Federer, who has secured his eighth consecutive invitation.

Three-time Wimbledon finalist Roddick made the semi-finals in 2003 and 2004 in Houston and 2007 at Shanghai.

"The reaction I received from fans after the Wimbledon final was something I will never forget. I've always had great support in London and I'm looking forward to being back there in November. I'm sure it will be a fantastic event," said Roddick.

Shanghai champion Nikolay Davydenko stands next to qualify, leading Spain's Fernando Verdasco by 420 points. (dpa)