The PGA Tour has suspended all current and future players who have decided to join the Saudi-backed LIV Golf Invitational Series that began on Thursday.
PGA Tour Commissioner Jay Monahan sent a letter to members that said those who join the lucrative breakaway series will not be permitted to play on the US-based circuit as a non-member via a sponsor exemption or any other eligibility category.
Among the players who have already joined LIV Golf are Phil Mickelson, who counts six major championships among his 45 PGA Tour wins, and former world No 1 Dustin Johnson.
"These players have made their choice for their own financial-based reasons. But they can't demand the same PGA Tour membership benefits, considerations, opportunities and platform as you," Monahan said in the letter to PGA Tour members. "That expectation disrespects you, our fans and our partners.
"You have made a different choice, which is to abide by the Tournament Regulations you agreed to when you accomplished the dream of earning a PGA Tour card and – more importantly – to compete as part of the preeminent organization in the world of professional golf."
Both the PGA Tour and DP World Tour had declined requests from members who had asked for releases to compete at Centurion Club this week outside London where $25 million is up for grabs, including $4 million for the winner.
The decision by the PGA Tour triggered a quick and scathing response from LIV Golf.
"Today's announcement by the PGA Tour is vindictive and it deepens the divide between the Tour and its members," LIV Golf said in a statement.
"It's troubling that the Tour, an organization dedicated to creating opportunities for golfers to play the game, is the entity blocking golfers from playing.
"This certainly is not the last word on this topic. The era of free agency is beginning as we are proud to have a full field of players joining us in London, and beyond."
The decision by the PGA Tour, which does not run golf's four majors, came after the United States Golf Association said it would allow LIV golfers who to play in next week's U.S. Open if they are exempt or had already qualified.