Greg Norman has accused the PGA Tour of bullying and threatening its players by warning them they might face a lifetime ban if they join a proposed rival circuit that is being financed by Saudi Arabian money.

In a letter to PGA Tour commissioner Jay Monahan on Thursday, a copy of which was obtained by ESPN, Norman accused Monahan of “going too far, being unfair” and likely breaking labor laws.

“Simply put, you can’t ban players from playing golf,” Norman wrote. “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?”

The PGA Tour has told players that anyone who competes in the proposed Super Golf League would face an immediate suspension and a possible lifetime ban. Monahan reiterated the tour’s stance during meetings with players in California last week and Florida this week.

Monahan told The Associated Press on Wednesday that he made it clear to the players that there is “zero complacency” when it comes to the Saudi league and that any player who signs up with the new circuit would lose their PGA Tour membership.

“I told the players we’re moving on and anyone on the fence needs to make a decision,” Monahan told the AP.

Norman, the CEO of LIV Golf Investments, has been the frontman for the Saudi-backed tour, which hoped to begin play this summer. It planned to have 14 events, including as many as 10 in North America. The rival league had hoped to poach top players, but many of the world’s best have pledged their allegiance to the PGA Tour, including Jon Rahm, Justin Thomas, Rory McIlroy, Dustin Johnson and Bryson DeChambeau.

In the letter, Norman, a former world No. 1 and two-time winner of The Open, accused the PGA Tour of putting its “own financial ambitions ahead of the players, and every player on the tour knows it.”

“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 wrote. “But when you threaten to end players’ careers and when you engage in unfair labor 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.”

While the recent commitments to the PGA Tour from Johnson, DeChambeau and others might have been big blows to the proposed breakaway league, Norman doesn’t seem ready to give up his efforts.

“Commissioner — this is just the beginning,” Norman wrote. “It certainly is not the end.”