The first of what could be multiple legal challenges to the PGA Tour’s decision to suspend players for defying regulations and playing the LIV Golf circuit landed in a California court Wednesday.

In what was first reported by the Wall Street Journal, Phil Mickelson and Bryson DeChambeau were among 11 players who filed a lawsuit in the U.S. District Court Northern District of California claiming the Tour has violated antitrust law.

“The Tour’s unlawful strategy has been both harmful to the players and successful in threatening LIV Golf’s otherwise-promising launch,” the 105-page lawsuit claimed. “The Tour flexed its incumbent monopolistic power, including by enforcing its unlawful player restrictions that deny players the ability to sell their services to others, imposing lengthy suspensions on players for merely exercising their right as independent contractors to play in a competing promoter’s events, and ramping up its threats targeting Plaintiffs and others.”

The list of 11 players includes: Mickelson, DeChambeau, Talor Gooch, Hudson Swafford, Matt Jones, Abraham Ancer, Carlos Ortiz, Ian Poulter, Pat Perez, Jason Kokrak and Peter Uihlein. All have been suspended by the PGA Tour for competing in LIV Golf events but have not relinquished their Tour membership.

Three of those players – Gooch (20^th on the FedExCup points list), Jones (62^nd) and Swafford (63^rd) – are also seeking a temporary restraining order that would allow them to participate in the FedExCup Playoffs, which begin next week at the FedEx St. Jude Championship in Memphis.

“It’s an attempt to use the Tour platform to promote themselves and to freeride on your benefits and efforts. To allow reentry into our events compromises the Tour and the competition, to the detriment of our organization, our players, our partners and our fans,” read a memo from Tour commissioner Jay Monahan that was sent to players Wednesday. “The lawsuit they have filed somehow expects us to believe the opposite, which is why we intend to make our case clearly and vigorously.

“Let me be clear: we will continue to defend the members who abide by the regulations written by and for the players.”

The Tour appeared to brace for an eventual challenge to the suspensions when it created an alternate points list last week that excluded the suspended players from playoff eligibility. The circuit moved to ensure, “that suspended members do not negatively impact other players’ tournament eligibility, positioning on the priority rankings or eligibility to compete in the FedExCup playoffs," according to a  previous memo to players from Monahan.

A spokesperson for LIV Golf responded to the lawsuit, saying, “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.”

Four players filed a similar challenge last month in the U.K. seeking an injunction to play the Scottish Open, which was co-sanctioned by both the PGA Tour and DP World Tour. Those players won a stay in court and were allowed to play.

LIV Golf CEO Greg Norman had previously said that the upstart circuit would financially “backstop” players with representation if they sought to legally challenge the PGA Tour. LIV Golf is bankrolled by Saudi Arabia’s Public Investment Fund.