ATP and Davis Cup joint event could happen - David Haggerty
International Tennis Federation president David Haggerty is "confident" a revamped Davis Cup and the new ATP Team Cup can join forces to create a single tournament.
Haggerty says "fruitful talks" have taken place between the ATP and ITF after concerns were raised about a congested player schedule.
"At the heart of the problem is the calendar," Haggerty said.
"Is there a way to collaborate and work together?"
The current Davis Cup format is getting an overhaul and being replaced by an 18-nation World Cup-style event to be held in Madrid in November 2019.
The ATP event, involving 24 international teams, will act as a curtain-raiser for the men's 2020 season just six weeks later.
"We are all responsible for making sure the players have a flow throughout the season, so they can start and finish strong," added Haggerty.
Germany's ATP Finals champion Alexander Zverev says he would be reluctant to play at the Davis Cup in late November and Tomas Berdych has also criticised the plans.
The ATP event has been backed by world number one Novak Djokovic, but he also said creating two "average events" would not be good for the sport.
France are currently hosting Croatia in the final of the last ever home and away Davis Cup.
The ITF agreed to reform the Davis Cup in August, with a $3bn (£2.34bn), 25-year partnership agreed with Kosmos, the investment group founded by Barcelona defender Gerard Pique.
Haggerty said: "We had very productive meetings in London with the ATP, Kosmos, the ITF, the Grand Slams and the players to talk about what is the best thing to do for tennis.
"We will meet again in January to continue the dialogue."