Jay Monahan, the commissioner of the PGA Tour, has vowed to "vigorously" fight a lawsuit filed against the organisation by 11 LIV Golf players.
Earlier today, a group comprising Phil Mickelson and Bryson DeChambeau and others lodged a suit seeking to overturn indefinite suspensions they were issued by the PGA Tour after committing to play on the new Saudi-funded enterprise.
As part of that suit, three players - Talor Gooch, Matt Jones and Hudson Swafford - are seeking a temporary restraining order to play in the FedEx Cup Playoffs which get under way in just over a week's time.
The trio were inside the top-125 on the rankings at the time of their defection to LIV and cannot be overtaken.
In a missive issued to PGA Tour members this evening, Monahan wrote: "We have 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.
"Fundamentally, 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're trying to use lawyers to force their way into competition alongside our members in good standing."
He added: "It's an attempt to use the tour's 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 organisation, our players, our partners and our fans.
"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."
Monahan also encouraged PGA Tour members to "speak out publicly on this issue, if you are so inclined."
He concluded: "This is your tour, built on the foundation that we work together for the good and growth of the organisation... and then you reap the rewards. It seems your former colleagues have forgotten one important aspect of that equation."
The fight for control of men's professional golf just got a whole lot uglier.