McIlroy stated on numerous occasions that he did not think LIV players should be available for selection for this year's Ryder Cup in Rome, where he and Rahm played starring roles in helping Europe to a convincing victory over the US.
However, the world number two believes the deal between the DP World Tour, PGA Tour and Saudi Arabia's Public Investment Fund has "legitimised" LIV and wants Rahm on Luke Donald's side when they attempt to retain the trophy at Bethpage Black in 2025.
"Jon is going to be in Bethpage in 2025 so, because of this decision, the European Tour (DP World Tour) are going to have to rewrite the rules for the Ryder Cup eligibility, absolutely," McIlroy told Sky Sports.
Rory McIlroy celebrates winning his singles match in Italy. (AP PHOTO)
"There's no question about that - I certainly want Jon Rahm on the next Ryder Cup team.
"I'm going to miss competing against him week in and week out. He's got so much talent, he's so tenacious, he's a great team-mate in the Ryder Cup.
"Is it disappointing to me? Yes. But the landscape of golf changed on June 6, when the framework agreement was announced. I think, because of that, it made the jump from the PGA Tour to LIV a little easier for guys.
"They let the first guys really take the heat and then this framework agreement legitimised basically what LIV was trying to do. I think it's made it easier now if that's really what you want to do."
As things stand, Rahm will be eligible for the Ryder Cup as long as he remains a DP World Tour member, which requires him to play in four regular tournaments per season.
He will also earn points towards qualification through major championships, but faces fines and suspensions for playing in LIV tournaments without the required "conflicting event" releases from the DP World Tour.
Jon Rahm was a key member of the winning European team. (AP PHOTO)
In April this year, an arbitration panel ruled that the Tour had the right to sanction players for such "serious breaches" of its code of behaviour, a case sparked by 12 players appealing against fines of £100,000 (A$190,000) and suspension from the Scottish Open for playing LIV's inaugural event in June 2022.
Sergio Garcia, Ian Poulter and Lee Westwood resigned their memberships in the wake of the arbitration panel's decision, while Henrik Stenson was sacked as Ryder Cup captain after joining the Saudi-funded breakaway.
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