STORY: The PGA Tour has suspended 17 golfers - including fan favorite Phil Mickelson - for joining the controversial LIV Invitational Series.
Mickelson teed off at the Saudi-backed competition on Thursday.
With $25 million dollars up for grabs, it's the most lucrative tournament in the sport's history.
In a letter to members, PGA Tour Commissioner Jay Monahan accused LIV participants of 'turning their backs' on the U.S. based circuit for 'financial-based reasons'.
Their suspensions are indefinite.
LIV Golf knocked the move as “vindictive” - and said it "deepens the divide between the Tour and its members."
Mickelson stayed mum on the issue, while former Masters champion Sergio Garcia said he wasn’t fazed.
“Any PGA tour matters, I’m not going to discuss publicly at this time.”
“It doesn’t bother me. I’m very happy where I am. I’m excited for this tour, I thought today was a great day to start and that’s where I'm going to focus. I resigned a week and a half ago so what the PGA tour said doesn’t go with me because I’m not a member.”
The developments come amid a bitter power struggle rocking golf's foundations.
The money on offer from LIV has lured some of golf’s biggest names away from the established PGA Tour.
Speaking earlier in the week, Northern Irish golfer Graeme McDowell defended his participation.
“You know, it would be crazy to walk away from that as a businessman.”
But the breakaway series is bankrolled by Saudi Arabia’s Public Investment Fund, which critics say is an attempt to burnish the country’s reputation in light of human rights concerns through so-called “sportswashing.”
The competition takes place during the PGA’s Canadian Open.
It’s one of the world’s most established golf tournaments - but offers a far smaller prize of $8.7 million.
Rory McIlroy is hoping to defend his title there and accused the LIV golfers as being turned by “boatloads of cash.”
After London, the LIV Series has four events in the United States, one in Thailand, one in Saudi Arabia before a team finale at Donald Trump's course in Miami.