Dustin Johnson confirmed for LIV Golf Invitational Series opener at Centurion

Former world No 1 will be joined by Garcia, Westwood, and Kaymer, although Mickelson was not on the initial list

Dustin Johnson will be the highest-ranked player in the field at the LIV Golf Invitational Series opener at Centurion Club. Getty

Former world No 1 Dustin Johnson was a surprise inclusion for the opening LIV Golf Invitational Series event in a field which also includes former Masters champion Sergio Garcia, although Phil Mickelson was not on the initial list.

While six-time major champion Mickelson was not on the field list, he could still tee it up at the Saudi-backed league event on June 9-11 at the Centurion Club outside London as six spots in the 48-player tournament remain open.

Among the other notables included are former world No 1s Lee Westwood and Martin Kaymer, as well as European Ryder Cup veteran Ian Poulter. The final six players will be announced at a later date, LIV Golf said.

World No 13 Johnson, a two-time major champion, is the highest-ranked player in a field that currently includes 26 of the top 150 golfers in the world.

"Free agency has finally come to golf," said LIV Golf CEO Greg Norman. "This is an opportunity to start a movement that will change the course of history by bringing new and open competition to the sport we all love.

"The desire shown by the players to participate in LIV Golf demonstrates their emphatic belief in our model and confidence in what we're building for the future."

Mickelson, 51, has been linked to LIV Golf for months but has been on a self-imposed hiatus from the sport since February – even skipping his title defence at the PGA Championship – amid backlash over comments he made about the PGA Tour and breakaway tour.

Both the PGA Tour and DP World Tour have recently declined all requests from members who had asked for releases to compete at Centurion, where $25 million is up for grabs, including $4m for the winner.

Sergio Garcia will compete at Centurion Club. AFP

It is unknown whether those competing in the lucrative breakaway circuit's first event, which is being held opposite the PGA Tour's Canadian Open – where the winner will get $1.57m from an $8.7m purse – will face consequences.

Organisers of the Canadian Open said they were disappointed with Johnson, who was expected to play in Toronto and is an ambassador for RBC, the title sponsors of the tournament.

"Together with our partners at RBC, we are disappointed to learn at this late stage that Dustin Johnson has made the decision to play the LIV Golf event," they said in a statement.

"As a past RBC Canadian Open champion, Canadian golf fans were looking forward to DJ's return this year."

Phil Mickelson was excluded from the initial field list for the opening LIV Golf Invitational Series event. AP

Mickelson, who has 45 PGA Tour wins, has not played on the US-based circuit since January and last competed in early February at the Saudi International, an Asian Tour event.

Johnson, who in February said he was "fully committed" to the PGA Tour, ultimately decided the opportunity was too good to pass up, his agent David Winkle told Golf Channel.

"Dustin's been contemplating this for the past two years and decided it was in his and his family's best interest to pursue it," Winkle said. "He's never had any issue with the PGA Tour and is grateful for all it's given him but in the end felt this was too compelling to pass up."