In perhaps the biggest blow to the PGA Tour, defending Masters champion Jon Rahm announced on Thursday on Fox News Channel that he joined LIV Golf.

Rahm had previously been critical of the league, even once saying that $400 million would not change his lifestyle. However, amid rumors that an offer reached $600 million, Rahm is off to the Saudi-funded league.

At the time of the decision, Rahm ranked third in the world, behind only Scottie Scheffler and Rory McIlroy, the latter of whom has been adamant in his distaste for LIV.

However, when news of Rahm's decision broke, he seemed to soften his stance and understand where Rahm was coming from.

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Rory McIlroy and Jon Rahm at Ryder Cup

Rory McIlroy, left, and Jon Rahm of Team Europe celebrate following victory with a 16 and a half to 11 and a half win following the Sunday singles matches of the 2023 Ryder Cup at Marco Simone Golf Club on Oct. 1, 2023 in Rome. (Patrick Smith/Getty Images)

"It's hard to sit here and criticize Jon because of what a great player he is and the experiences I've had with him. All I would say is that I'll be disappointed to not play against him more regularly in the future," McIlroy said.

"I am going to miss competing against him week-in-week-out," he added. "He is such a good player, he's got so much talent. He is so tenacious, and a great teammate at the Ryder Cup. I have nothing but good things to say about Jon. I respect the hell out of him as a golfer.

"He seems like he wants to live his life the right way. He wants to be a good dad, he wants to be a good husband. You can't judge someone for making a decision that they feel is the best thing for them."

McIlroy and Rahm were key factors in helping Team Europe to a Ryder Cup victory in Rome back in October. However, as it currently stands, Europeans must be in the DP World Tour (formerly the European Tour) in order to qualify. 

That forced Ryder Cup veterans Sergio Garcia, Lee Westwood, Ian Poulter and former captain Henrik Stenson to miss this year's event, and with his move to LIV, Rahm is currently out of the 2025 event at Bethpage Black in New York.

However, McIlroy says the DP World Tour has no choice but to change its rules for Rahm.

Jon Rahm and Rory McIlroy high five

Jon Rahm, left, shakes hands with Rory McIlroy on the 1st tee on Day One of The 151st Open at Royal Liverpool Golf Club on July 20, 2023 in Hoylake, England. (Gregory Shamus/Getty Images)

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"Jon is going to be in Bethpage in 2025. So because of this decision, the European Tour are going to have to rewrite the rules for Ryder Cup eligibility," McIlroy pleaded. "Absolutely, there is no question about that. I certainly want Jon Rahm on the next Ryder Cup team."

Rahm is 6-3-3 in his dozen Ryder Cup matches, including a perfect 4-0-0 in foursome play.

As for the sport itself, McIlroy worries that if LIV continues to steal PGA's players and make it difficult for golf fans to focus on two tours, the popularity of the sport will die.

"To me, having all the best golfers under the one umbrella is the best way forward because I think that's really what the public wants., he said. The majors are already so big, but my fear is that if we keep going down this path then all the best players are only going to get together four times a year. That means golf is only going to be relevant four times a year and that's good for no one in the game.

Rahm and Rory

Rory McIlroy, right, and Jon Rahm of Team Europe celebrate following victory with a 16 and a half to 11 and a half win following the Sunday singles matches of the 2023 Ryder Cup at Marco Simone Golf Club on Oct. 1, 2023 in Rome. (Patrick Smith/Getty Images)

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"We need to get everyone back together and try to forget about what has happened in the past. Let bygones be bygones and we all move forward together - I think that's what's going to be the best thing for the professional game."