A U.S. District Court judge granted a motion allowing the PGA Tour to add the Saudi Arabia Public Investment Fund (PIF) and PIF governor Yasir Al-Rumayyan as defendants in its countersuit against LIV Golf, according to ESPN's Mark Schlabach.

As a result of her ruling on Tuesday, Judge Beth Labson Freeman provided the PGA Tour's attorneys a period of leave to amend their countersuit. She determined the delay wouldn't cause undue harm to LIV Golf or its golfers.

Schlabach reported in January the PGA Tour was looking to list the PIF as a defendant as well as Al-Rumayyan for allegedly helping golfers breach their contracts and sign with LIV Golf.

Attorneys for the tour contended the two parties "played an active and central role in orchestrating these breaches for their own benefit and are equally liable for the harm caused to the TOUR," per Schlabach.

The PGA Tour also argued the PIF and Al-Rumayyan are "exercising near absolute authority over LIV" and have worked directly to bring in golfers.

Al-Rumayyan said in a sworn statement the PIF only maintains "high level oversight" when it comes to LIV Golf.

Judge Freeman's decision is another legal setback for LIV.

Last Thursday, U.S. Magistrate Judge Susan van Keulen ruled the PIF and Al-Rumayyan can be deposed by PGA Tour attorneys and don't have sovereign immunity in this case. Van Keulen believes they aren't covered under the Foreign Sovereign Immunities Act because they're conducting commercial business in the United States.

The courtroom battle began in August, when Phil Mickelson and 10 other LIV golfers filed an antitrust suit against the PGA Tour. The golfers, who had recently been suspended from tour events, argued the PGA Tour was acting as a monopoly and directly threatening their professional careers.

The tour filed its countersuit in September and alleged LIV Golf "has openly sought to damage the Tour's business relationships with its members by inducing them to breach their contractual requirements, even going so far as to pay members' legal fees to make breaching their contracts with Tour more enticing."