Greg Norman has written an open letter to PGA Tour commissioner Jay Monahan, accusing him of “bullying” players with “unenforceable” threats of a lifetime ban if they join a rival league.

In a meeting with players earlier this week, Monahan reiterated that those who joined the proposed Saudi-backed circuit, which is being spearheaded by former world number one Norman, would be banned by the PGA Tour.

That looked something of a moot point with Rory McIlroy describing the breakaway as “dead in the water” after Dustin Johnson and Bryson DeChambeau pledged their future to the PGA Tour in the wake of Phil Mickelson’s explosive comments about the new venture.

However, Brooks Koepka conceded on Wednesday that some players would still “sell out” and join the breakaway and Norman insists “this is just the beginning” at the end of his 500-word letter.

The letter reads: “Dear Commissioner Monahan: Surely you jest. And surely, your lawyers at the PGA Tour must be holding their breath.

“As has been widely reported, you have threatened the players on the PGA Tour, all of whom are independent contractors, with lifetime bans if they decide to play golf in a league sponsored by anyone other than the Tour.

“For decades, I have fought for the rights of players to enjoy a career in which they are rewarded fully and properly for their efforts. They are one-in-a-million athletes.

“Yet for decades, the Tour has put its own financial ambitions ahead of the players, and every player on the tour knows it. The Tour is the Players Tour not your administration’s Tour.

“Why do you call the crown jewel in all tournaments outside the Majors “The Players Championship” and not “The Administration’s Championship?”

“But when you try to bluff and intimidate players by bullying and threatening them, you are guilty of going too far, being unfair, and you likely are in violation of the law.

“Simply put, you can’t ban players from playing golf. Players have the right and the freedom to play where we like. I know for a fact that many PGA players were and still are interested in playing for a new league, in addition to playing for the Tour. What is wrong with that?

“What is wrong with allowing players to make their own decisions about where to play and how often to play? What is so wrong with player choice? Why do you feel so threatened that you would resort to such a desperate, unwise, and unenforceable threat?”

Norman goes on to cite an article by Alden Abbott, the former general counsel of the Federal Trade Commission, in which the author claims that a ban would trigger a “slam-dunk antitrust lawsuit”.

“Competition in all aspects of life, sport, and business is healthy and the players deserve to be well compensated, which is why so many players have expressed an interest in playing in a new league,” Norman adds.

“But when you threaten to end players’ careers and when you engage in unfair labour practices with your web of player restrictions, you demonstrate exactly why players are open minded about joining a league that treats players well, respects them, and compensates them according to their true worth.

“Commissioner – this is just the beginning. It certainly is not the end.”