Eleven LIV Golf players, including Phil Mickelson and Bryson DeChambeau, filed an anti-trust lawsuit on Wednesday against the US PGA Tour, some seeking a restraining order to compete in next week's playoffs.

The lawsuit, filed in federal court in the Northern District of California, challenges the indefinite suspensions imposed by PGA commissioner Jay Monahan upon those who played in any of the Saudi-backed upstart tour's first three events.

The lawsuit begins a legal showdown between the rebel series and the established PGA Tour and whether the golfers are free agents or as tour members are subject to rules and punishments of the PGA Tour.

With LIV Golf events offering record $25 million purses and some players reportedly offered fat signing bonuses as well, some top names joined the circuit despite criticism over Saudi human rights abuses.

"As the tour's monopoly power has grown, it has employed its dominance to craft anti-competitive restraints to protect its long-standing monopoly," the lawsuit claimed.

"Threatened by the entry of LIV Golf and diametrically opposed to its founding mission, the tour has ventured to harm the careers and livelihoods of any golfers... who have the temerity to defy the tour and play in tournaments sponsored by the new entrant.

"The tour has done so in an intentional and relentless effort to crush nascent competition before it threatens the tour's monopoly."

Australian Matt Jones and Americans Talor Gooch and Hudson Swafford want a temporary restraining order to be able to compete in next week's first PGA Tour FedEx Cup playoff event at Memphis. They qualified based on season points before joining LIV Golf and being banished.

Other players filing the lawsuit include Mexico's Abraham Ancer and Carlos Ortiz, England's Ian Poulter and Americans Jason Kokrak, Pat Perez and Peter Uihlein.

A memo from PGA commissioner Jay Monahan to players obtained by The Golf Channel said the tour was confident in its legal position regarding the suspensions.

"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," the memo stated.

"These suspended players, who are now Saudi Golf League employees, have walked away from the tour and now want back in.

"With the Saudi Golf League on hiatus, they are trying to use lawyers to force their way into competition alongside our members in good standing. It's an attempt to use the tour platform to promote themselves and to free ride on your benefits and efforts.

"To allow entry into our events compromises the tour and the competition to the detriment of our organization, our players, our partners and our fans."

LIV Golf backed the lawsuit in a statement to The Golf Channel.

"The players are right to have brought this action to challenge the PGA Tour's anti-competitive rules and to vindicate their rights as independent contractors to play where and when they choose," the LIV Golf Series statement said.

"Despite the PGA Tour's efforts to stifle competition, we think golfers should be allowed to play golf."

The move came on the eve of the PGA's Wyndham Championship at Greensboro, North Carolina, and sparked emotional reactions.

"It just feels like a quick cash grab for those guys," said American J.T. Poston. "The money that's being used to fight those lawsuits are coming out of our pockets."

As for LIV Golf players possibly in the PGA playoffs, Poston added, "I don't know if there will be hostility but I know there are some bridges that have been broken. Some guys will not appreciate that."

US 2023 Ryder Cup captain Zach Johnson called the lawsuit "extremely unfortunate," adding, "it's sad it has come to this. You should pick one and that's the route you should have to go."

"You can't have it both ways," said American Will Zalatoris. "We've been grinding all year and they are doing something detrimental.

"I think a lot of guys would be pretty frustrated if they are allowed to do both. Deep down all of us share the same feelings."

"It's frustrating," said American Billy Horschel. "They made a decision to leave the PGA Tour. They should follow their employer. A lot of guys are not very happy."