(CNN) The Saudi-backed LIV Golf Invitational Series has joined the antitrust lawsuit against the PGA Tour in an amended complaint in which four golfers originally listed on the original lawsuit have withdrawn their names.
Carlos Ortiz, Abraham Ancer, Pat Perez and Jason Kokrak withdrew their names, leaving just seven golfers including six-time major champion Phil Mickelson and Bryson DeChambeau along with LIV Golf as the plaintiffs in the lawsuit.
Earlier this month, 11 golfers participating in the LIV Golf series filed an antitrust lawsuit to challenge their suspensions by the PGA Tour.
Three golfers still listed on the lawsuit -- Matt Jones, Talor Gooch and Hudson Swafford -- had their request for a temporary restraining order to play in the FedEx Cup playoffs denied by a judge earlier in August.
The amended complaint was filed on Friday in the US District Court in Northern California.
According to the amended complaint, LIV Golf is seeking "punitive damages against the PGA Tour for its tortious interference with LIV Golf's prospective business relationships."
PGA Tour said they were "aware" of the amended complaint but had no comment. CNN has reached out to LIV Golf but did not immediately hear back.
The LIV Golf series is backed by Saudi Arabia's Public Investment Fund (PIF) -- a sovereign wealth fund chaired by Mohammed bin Salman, the Crown Prince of Saudi Arabia and the man who a US intelligence report named as responsible for approving the operation that led to the 2018 murder of journalist Jamal Khashoggi. Bin Salman has denied involvement in Khashoggi's murder.
According to the PGA Tour, any golfer that joined LIV Golf was ruled ineligible to participate in tournament play since early June.
LIV Golf's next three-day event is scheduled to begin September 2 in Boston.