Shock as Oosthuizen, Grace, Schwartzel resign from PGA Tour to play Saudi-backed series

South Africa's top-ranked golfers Louis Oosthuizen, Branden Grace and Charl Schwartzel have resigned their membership from the PGA Tour to play in the Saudi-backed LIV Golf series.

Oosthuizen confirmed that he has given up his PGA Tour membership card at Centurion Club on Tuesday ahead of this week's inaugural LIV event.

Former world number one and two-time major champion Dustin Johnson also resigned from the PGA Tour along with 2017 Masters champion Sergio Garcia, Northern Ireland's Graeme McDowell and Kevin Na.

Players who opted into the LIV Golf series were given warnings from the PGA Tour and that they will face disciplinary action.

This week's event tees off at Centurion Club at St Albans, north of London, and will have a $25 million purse (almost double that of any major) with $4 million going to the winner.

In the press conference on Tuesday morning, Oosthuizen revealed that his reasoning for abandoning the PGA Tour had to do with his family.

"For me, where I am at in my career, it would've probably been the last year on the PGA Tour," Oosthuizen told reporters at Centurion Club.

"I always said, when I get to the stage around 40, I want to do something else and not just golf. I wanted to try something else. 

"Everyone knows I love being on a farm and being outside, so I was almost done. And along came this opportunity, where I can do four years of this quickly and be able to spend more time with my family after this. 

"The format and the way this is all set up is so exciting and it reminded me of being part of the Presidents Cup and I just said, 'Why not give it a shot?'

"I made the decision with my wife and what's the best for where I am right now and I'm going to grab it and play. I'm a professional golfer and this is