The pair, plus Talor Gooch and Hudson Swafford, were part of a group of 11 who had sought damages and a temporary injunction to allow the latter two to feature the FedEx Cup play-offs.
Carlos Ortiz, Pat Perez, Jason Kokrak and Abraham Ancer had all withdrawn before the injunction was denied by a US district court in North California and the latest withdrawals leave only Matt Jones, Bryson DeChambeau and Peter Uihlein as current players.
The Saudi-backed LIV Golf, as an organisation, joined the lawsuit late last month ahead of a trial scheduled for January.
“Nothing has changed. The merits of the lawsuit — the PGA Tour’s anti-competitive conduct — still stand and will be fully tested in court, and we look forward to it,” said a LIV Golf statement to Sports Illustrated.
“We stand by the players who the PGA Tour has treated so poorly, but we also recognise to be successful we no longer need a wide variety of players to be on the suit.
“We have our players’ backs and will press our case in court against the PGA’s anti-competitive behaviour.”
Both Mickelson and Poulter said, with LIV joining the lawsuit, they no longer felt they needed to pursue the case individually.
“With LIV’s involvement in these issues, the players’ rights will be protected and I no longer feel it is necessary for me to be part of the proceedings,” Mickelson said in a statement.
Poulter, who also was among a number of players to apply for an injunction against the DP World Tour in order to allow them to play in July’s Scottish Open and subsequent events, said similar.
He said: “Now that I’m no longer a member of the PGA, and with LIV’s involvement in these important issues, I have decided to forego my involvement in this matter. I have faith LIV will successfully make the legal case.”
In response to the lawsuit when it was filed last month, PGA Tour commissioner Jay Monahan said in a memo written to players: “We have been 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.”
