The European Tour is opposing in “the strongest possible terms” renewed plans for a breakaway Premier Golf League.
The PGL proposed last January that 48 players would compete in an 18-event season offering a prize fund of £183m.
Rory McIlroy, who was world number one at that time, ruled himself out.
Jon Rahm and Brooks Koepka, then ranked two and three in the world, also said they would not play in the proposed league.
In November, the European Tour and PGA Tour agreed a “strategic alliance”, with PGA Tour commissioner Jay Monahan also taking a seat on the European Tour’s board.
In a statement on Wednesday, European Tour chief executive Keith Pelley said: “We are aligned with the PGA Tour in opposing, in the strongest possible terms, any proposal for an alternative golf league.
“Since the launch of our strategic alliance last November, our two organisations have been working together to make global golf less fractured and not create further division, with the interests of all players and fans at the forefront of our thinking.”
Former US Open champion Webb Simpson believes the new proposal is “far fetched”.
Speaking before this week’s Wells Fargo Championship at Quail Hollow, he said: “It’s hard for me to believe it’s really going to happen and the guys will really jump ship and go to a completely different way of golf than we’ve always had.
“Purses are going up, seems like we play better golf courses. Everything seems to be getting better with the PGA Tour.
“Are the best players in the world really going to go to this tour if only eight of the top 25 in the world ranking are going to go?
“As a top player I want to play against the best.
“You create a new tour, all these records get kind of thrown out the window, I want to go after records, not a dollar.”
Northern Ireland’s McIlroy, who has been elected chairman of the PGA Tour’s player advisory council for 2021, is due to speak in his pre-tournament news conference at around 14:50 BST on Wednesday.