Four-times major winner Rory McIlroy believes the PGA Tour will eventually merge with the European Tour as it is "counter-productive" for them to compete against each other.
McIlroy said one way of achieving a unified circuit would be if the US-based circuit bought the European Tour and continued to run its events.
"The World Tour - it's going to happen one day and I think it has to," McIlroy, who failed to qualify for this week's Tour Championship in Atlanta, told the "No Laying Up" golf podcast.
"To have all these tours competing against each other, and having to change dates, it's counter-productive. I think everyone has to come together, added the 28-year-old, who claimed the FedEx Cup title with victory in Georgia last year.
"The easy thing would be for the PGA Tour to buy the European Tour and take it from there. They could still run the European events and we'll have, say, 12 big events a year, outside the majors, a bit like they do in tennis.
"I don't see any other way. I know discussions have taken place, so maybe one day."
Hampered by rib and back injuries all season, McIlroy had planned to take three months off at the end of the year to recover full fitness but confirmed his participation in next month's British Masters and Alfred Dunhill Links Championship.