Roddick, the current number one and U.S. Open champion, was the only 2003 Grand Slam winner in the red group, being drawn alongside Argentine Guillermo Coria, Germany's Rainer Schuettler and Spaniard Carlos Moya.
Spain's Juan Carlos Ferrero, the world number two hoping to dislodge Roddick at the season-ending championship, was automatically kept apart from Roddick at the head of the blue group.
But French Open champion Ferrero nevertheless has the tougher challenge ahead after being pitted against big guns Roger Federer of Switzerland, American Andre Agassi and Argentine David Nalbandian.
Wimbledon champion Federer, third in the Champions Race and the entry system rankings, also has an outside chance of finishing 2003 at the top, according to the ATP Tour.
Agassi has not played since losing to Ferrero in the semi-finals of this season's U.S. Open, but the 33-year-old has won four times this year, including the Australian Open and ATP event at Houston, and is aiming for his second season-ending championship triumph.
Roddick, winner of six tournaments this season, including his first major at Flushing Meadows in September, missed out on a chance to put clear water between himself and Ferrero in the rankings by losing to eventual winner Tim Henman in last week's Paris Masters semi-finals.
SPANISH RIVAL
Roddick now leads his Spanish rival by just 26 points in the Champions Race, which means every match at the eight-man Masters Cup will matter.
Players get 20 Champions Race points for winning each of their three round-robin matches, 40 for a semi-final win and a further 50 for the title.
"I will do everything in my power to be world number one," Ferrero said in Paris last week.
"Andy has to play well at the Masters Cup to be world number one, so we will fight for it."
The Masters Cup event brings together the top eight players in the ATP Champions Race.
Roddick, Coria, Nalbandian and Schuettler make their debuts at the season-ending championship, while the presence of Coria and Nalbandian represents the first time since Guillermo Vilas and Jose-Luis Clerc in 1982 that two Argentines have qualified.
Australian Lleyton Hewitt, the winner of the event in 2001 and 2002, did not qualify this year.
