Jordan Spieth, who took McIlroy's spot on the board in November, raised eyebrows this week with his comments that the merger may no longer be necessary for the PGA Tour.
Speith's remarks came after the PGA Tour announced a new partnership and investment deal with the Strategic Sports Group (SSG).
SSG includes a number of high-powered sports owners including the Fenway Sports Group, owners of English Premier League club Liverpool, MLB's Boston Red Sox and the NHL's Pittsburgh Penguins.
The deal would see players collectively access more than $1.5 billion in grants that vest over time with SSG investing an initial $1.5 billion (£1.18 billion) and up to another $1.5 billion later.
Spieth reacted to that deal on Wednesday saying while he would be fine with a merger on the right terms for the players, it was no longer necessary.
"I don't think that it's needed. I think the positive would be a unification, but I just think it's something that is almost not even worth talking about right this second given how (long a time) everything would be to try to get it figured out," he said, referring to the ongoing negotiations and US lawmakers' investigations into Saudi investments in US sports businesses.
LIV is owned by the Saudi sovereign wealth fund, PIF, which has bankrolled the recruitment of a number of the sport's top stars, most recently reigning Masters champion Jon Rahm.
How would PIF react?
Sports Illustrated reported on Saturday that McIlroy, who has dropped his former hostility to LIV with a more conciliatory tone, confirmed he spent an hour talking to Spieth about his comments.
"My thing was if I'm the original (potential) investor that thought that they were going to get this deal done back in July, and I'm hearing a board member say that we don't really need them now, how are they going to think about that? What are they going to feel about that?" McIlroy told SI, recalling his call with Spieth.
"They are still sitting out there with hundreds of billions of dollars, if not trillions, that they're going to pour it into sport. And I know what Jordan was saying, I absolutely know what he was saying and what he was trying to say. But if I were PIF and I was hearing that coming from here, the day after doing this SSG deal, it wouldn't have made me too happy."
McIlroy said that if golf is to re-unite, PIF needs to be part of the new PGA Tour structure.
"Having PIF as your partner as opposed to not having them as your partner, I don't think is an option for the game of golf,” McIlroy said.
"I think they're committed to investing in golf and in the wider world of sport and, if you can, get them to invest their money the right way to unify the game of golf."
The conversation between Spieth and McIlroy came after the latter withdrew from a players' message group.
"I just want to remove myself from the fray a little bit," McIlroy said. "I talked to him about his comments. And we had a pretty frank discussion."
