Federer, who lost to Del Potro in the U.S. Open final, will also face Fernando Verdasco in Group A.
Second-ranked Rafael Nadal was drawn into Group B with Novak Djokovic, Nikolay Davydenko and Robin Soderling.
"Whoever you draw is going to be tough," said Murray, who reached the semifinals at the season-ending tournament in Shanghai last year. "Obviously I look forward to playing Roger. I've played Juan a few times on the tour recently and also had a close match recently with Verdasco indoors in Valencia.
"It's a tough group, but if I play well I think I have a good chance of qualifying."
The top two players in each group will advance to the semifinals of the season-ending tournament, which starts Sunday at the O2 Arena in London. The final is set for Nov. 29.
The tournament, which could earn an undefeated champion $1.63 million, features the top eight players in the world. Each round-robin match is worth $120,000, while the semifinal winners earn another $380,000 each. The champion will get an extra $770,000 for the win in the final.
Federer, who regained the No. 1 ranking from Nadal this season, could still be overtaken by the second-ranked Spaniard because an undefeated winner of the tournament will claim 1,500 points. Federer has 10,150 points heading into the tournament, and Nadal has 9,205.
Federer rebounded from a disappointing year in 2008 and completed a career Grand Slam by winning the French Open for the first time. He then reclaimed his Wimbledon title while breaking Pete Sampras' career Grand Slam record with his 15th major title.
In the other two Grand Slam tournaments, Federer lost in five sets in the finals - to Nadal at the Australian Open and to Del Potro at the U.S. Open.
Despite winning the Australian Open, Nadal struggled with injuries throughout the 2009 season. He lost to Soderling in the fourth round at Roland Garros and then pulled out of Wimbledon, where he was the defending champion. He made the semifinals at the U.S. Open, but again was hampered by injuries and lost to Del Potro.
Djokovic, who won the ATP World Tour Finals in Shanghai last year, seems to be in the best form heading into this year's tournament. The third-ranked Serb beat Federer in the Swiss Indoors final early this month, and then defeated Nadal in the Paris Masters semifinals en route to winning the tournament last Sunday.
Sixth-ranked Andy Roddick had been expected to play in London, but the Wimbledon finalist withdrew late Tuesday with a left knee injury. Ninth-ranked Soderling, who lost to Federer in the French Open final, is Roddick's replacement.
In doubles, Daniel Nestor and Nenad Zimonjic, Mahesh Bhupathi and Mark Knowles, Frantisek Cermak and Michal Mertinak, and Max Mirnyi and Andy Ram are in Group A. Bob Bryan and Mike Bryan, Lukas Dlouhy and Leander Paes, Lukasz Kubot and Oliver Marach, and Mariusz Fyrstenberg and Marcin Matkowski are in Group B.
Resino axed by AtleticoInjured Roddick pulls out of season-ending event
