Phil Mickelson, Bryson DeChambeau and nine other players who defected to the Saudi-funded LIV Golf filed an antitrust lawsuit Wednesday against the PGA Tour, the first step in a legal fight that could define the boundaries of where players can compete.

The lawsuit, filed in U.S. District Court in San Francisco, claims the PGA Tour has used monopoly power to try to squash competition and has unfairly suspended players.

A separate motion was filed asking for a temporary restraining order to allow Talor Gooch, Matt Jones and Hudson Swafford to play in the FedEx Cup playoffs, the PGA Tour's postseason, which begins next week.

The lawsuit also revealed that PGA Tour Commissioner Jay Monahan suspended Mickelson for two months in March for his role in recruiting players to LIV Golf. It said Mickelson's request in June to be reinstated was denied because he played in a LIV Golf event and that he was suspended until March 2024 for playing in another one.

Monahan responded to the lawsuit with a terse memo to his players in which he referred to "11 of your former colleagues" suing the tour and continued to refer to LIV Golf as the "Saudi Golf League."

Saudi Arabia's sovereign wealth fund is the primary source of the money paying exorbitant signing bonuses and providing US$25 million purses for 48-man fields. Several players are in their 40s and no longer ranked among the top 50 in the world.

Monahan said players knew the consequences of signing up for the rival league.

"We have been preparing to protect our membership and contest this latest attempt to disrupt our tour, and you should be confident in the legal merits of our position," Monahan wrote.

"Fundamentally, these suspended players -- who are now Saudi Golf League employees -- have walked away from the tour and now want back in," he wrote. "It's an attempt to use the tour platform to promote themselves and to freeride on your benefits and efforts."

LIV Golf said in a statement: "The players are right to have brought this action to challenge the PGA's anti-competitive rules and to vindicate their rights as independent contractors to play where and when they choose. Despite the PGA Tour's effort to stifle competition, we think golfers should be allowed to play golf."

Its CEO, Greg Norman, has said LIV Golf would be willing to financially support any legal matters. Last month, four European tour players won a temporary stay from a U.K. judge that allowed them to play in the Scottish Open.

Mickelson reportedly signed a deal worth $200 million to join the Saudi-funded venture, with DeChambeau in the $150 million range. And those are just signing bonuses. Seventeen players already have made more than $1 million in three tournaments or fewer.

The PGA Tour denied releases for players to compete in LIV events and suspended them as soon as they put a ball in play. Some players, like Dustin Johnson, Patrick Reed and Sergio Garcia, chose to resign their PGA Tour membership.

At the heart of the lawsuit are allegations the PGA Tour is using its might as the strongest tour in golf to bully players and anyone else that could get involved with LIV Golf. It accused the tour of intimidating a tent vendor and a technology company, among others, with whom LIV Golf was trying to do business to launch its series.

It also claims the tour's threats to ban players ultimately forced LIV Golf to pay more in signing bonuses to get the players it wanted, and forced the rival league to change its startup plans to only eight events this year. LIV Golf announced a 14-tournament schedule for next year.

"The Tour's conduct has substantially diminished and impaired the entry of the promoters that could meaningfully threaten the PGA Tour's monopoly, which has stood unchallenged for decades," the lawsuit contends.

The tour has stood by its belief that it is a membership organization with regulations that players choose to accept. That includes a code of conduct and a requirement to play at least 15 tournaments a year to keep full membership.

Players typically are allowed three releases a year to play overseas events held the same week as a PGA Tour tournament. The tour does not allow releases for conflicting events in North America.

Two LIV Golf events were held in the U.S., first in Oregon last month and then last week at Trump National in New Jersey. Three more this year are scheduled for courses near Boston, Chicago and Miami.

Monahan has been forceful in his comments about LIV Golf, referring in June to the tour being unable to compete with "a foreign monarchy that is spending billions of dollars in attempt to buy the game of golf."

"We welcome good, healthy competition. The LIV Saudi golf league is not that," he said. "It's an irrational threat, one not concerned with the return on investment or true growth of the game."