Federer and Djokovic are both primed to battle for the ATP finals title, with both men making the cut for the 02 Arena competition.
As well as the duo, Alexander Zverez, Marin Cilic, John Isner, Kevin Anderson, Dominic Thiem and Kei Nishikori are in the running for glory.
Roger Federer has been put in a group with Zverez, Cilic and Isner, who sit at third, fifth and eighth respectively in the ATP rankings.
And Becker believes the 37-year-old has been handed a more favourable draw compared to Djokovic.
“I would reckon the Novak Djokovic group is the tougher one,” said Becker.
“Djokovic, Zverev, Cilic, Isner is a pretty rough one.
“On the other hand, Kevin Anderson isn’t too bad either on serving.
“Normally the big servers prefer indoors because they have the advantage. Roger Federer has a big serve.”
One man who will not be competing is Rafael Nadal.
The Spaniard, who is No 1 in the world rankings behind Djokovic, is continuing his recovery from injury.
But Becker does not think his absence will make the competition less glamorous.
“Unfortunately we heard the news about Rafael Nadal,” he said.
“He was challenging for the no 1 spot with Novak Djokovic, who will now finish regardless, as the no. 1 player.
“But we have Roger Federer, Kevin Anderson, Alexander Zverev playing at the O2.”
Djokovic is the favourite going into the tournament.
He has triumphed in London four times in the past, and five times overall.
His most recent was in 2015, when he beat Federer in the final.
Federer, meanwhile, has achieved glory in the capital in 2010 and 2011.
And he has also won the ATP Finals in Houston and Shanghai, in 2003, 2004, 2006 and 2007.