Shortly after Conor McGregor lost Saturday’s boxing megafight to Floyd Mayweather, he gave MMA fans reason to rejoice by confirming that he would return to the UFC. McGregor has provided even more cause for excitement by saying that he would willing get back into the octagon against Nate Diaz and complete their trilogy.

Just one catch, though — the third fight would have to be at 155 pounds. That’s according to McGregor, who holds the UFC title at that weight and pointed out that it was “fair” of him to fight the first two times against Diaz at 170.

“I’m the 155-pound champion. I faced him at 170, he beat me, then I rematched him at 170, I beat him,” McGregor said (via bjpenn.com). “Now I’m the 155-pound world champion, now if he wants that fight, he must come down.

“So that’s a fair trade.”

After winning the UFC’s featherweight belt, at 145 pounds, in 2015, McGregor attempted to become the simultaneous lightweight champion in a 2016 match against Rafael dos Anjos. Just a couple of weeks before that fight, though, dos Anjos pulled out with an injury, leaving Diaz to step in on short notice.

Diaz did not have enough time to make weight at 155 pounds, so McGregor agreed to go all the way up to 170 for the fight, which Diaz won by submission in an upset. McGregor insisted that the rematch also be held at 170 pounds, and he went on to win that by majority decision.

Following that fight, McGregor defeated Eddie Alvarez for the lightweight crown in November, then took a long layoff, during which he became a first-time father, before squaring off with Mayweather. That event reportedly set pay-per-view records, and it earned both competitors tens of millions of dollars, causing fears among combat-sports fans that McGregor might never fight again.

“Everyone is like, ‘Oh, he’s going to retire — he made so much money.’ He’s ambitious. He’s super ambitious, and he loves to fight,” McGregor’s manager, Audie Attar, told MMA Junkie. “He loves to compete and he’s a superb professional athlete. So there’s much more of Conor McGregor that everybody will see, and we’ll see what’s next.”

What’s next for the Irishman could well be giving many fans what they want by offering Diaz a rubber match. That is, as long as McGregor’s antagonist is willing to make their third installment a lightweight, rather than welterweight, contest.

Diaz has spent most of his UFC career at lightweight, and he hasn’t fought at all since his two showdowns with McGregor, so he almost certainly would be on board with the terms of the fight. To McGregor, who is shorter in height and reach than Diaz, it’s only fair.

“I didn’t ask for the rematch at a lower weight, I asked for the rematch at the exact same weight,” he said. “I thought that was a fair-play move on my behalf, and I came in and I won. So, now I won that, and I won the 155 title after that, so if he wants the fight he has to make that 155 pound limit.”

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