The last time Conor McGregor walked to a UFC cage, he broke his leg against Dustin Poirier. That was July 10, 2021, and it was 1,827 days before he headlines UFC 329 on Saturday at T-Mobile Arena in Las Vegas. He returns at welterweight, 15 pounds north of where he built his name, against a man he already beat once, a very long time ago.

Max Holloway (27-9 MMA, 23-9 UFC) was a 21-year-old prospect when McGregor (22-6 MMA, 10-4 UFC) out-pointed him over three rounds at featherweight on Aug. 17, 2013. Gold confirms the result: a unanimous decision for McGregor, who, as MMA Fighting notes, blew out his own knee mid-fight and leaned on his grappling to survive the finish. Holloway went on to become one of the best featherweights the division has produced. McGregor became the biggest star the sport has ever had, then mostly stopped fighting. The rematch that arrives Saturday is not the fight the 2013 version promised.

The layoff is the whole story

Everything about this main event bends around one number: five years. McGregor has not competed since that 2021 doctor's stoppage loss to Poirier, the second straight defeat to Poirier and the injury that ended his run. Since then, Holloway has kept working. He knocked out Justin Gaethje to win the "BMF" belt in April 2024, beat Poirier by unanimous decision in July 2025, then lost that belt to Charles Oliveira on March 7 this year, out-grappled over five rounds. All of it is verified in gold.

That last fight is the one Belal Muhammad keeps coming back to. Breaking down the matchup on his YouTube channel, the welterweight champion argued Holloway should be the one to start the grappling, not sit back and wait. "Now five years off, extra muscle, higher weight class, I think his cardio's going to be even a bigger problem," Muhammad said of McGregor, per MMA Fighting. "So for Holloway, survive those first two, three minutes, even initiating the clinch, just stay away from the left hand."

It is a sharp read, and it points at the real question. Nobody, including the model, knows what a five-years-off McGregor looks like at welterweight. He has "definitely added a lot of muscle," Muhammad said, but muscle and a new weight class cut both ways: more power, and more to carry across 25 minutes.

What the model saw

The V14 model layer leans clearly to Holloway, giving McGregor roughly a 30% chance to win. Read alone, that looks like a confident call against the comeback. It isn't. We won't dress it up as one.

Our full four-input stack, the blend that carries the market price alongside three model voices, is far more cautious. It puts McGregor closer to 45% and tags the fight a TOSS-UP. That is the number we trust more here, and the reason is the layoff itself. A five-year gap at a brand-new weight is where the model's inputs are thinnest: recent-form signals go stale, the physical profile at 170 pounds has no track record, and there is no clean comparable in the data for a returning superstar of McGregor's kind. When the honest read is "we don't have the inputs to be sure," the responsible output is a coin-flip.

So the take is a lean, not a lock. The data narrowly favors Holloway, the market has him a modest favorite, and the correct confidence level is low. For context on what our conviction picks are worth when we do have the inputs, and this is not one of them, our flagged 2026 picks (LOCK and HIGH) sit at 82.67% (62-13, n=75) as of July 2026, against 68.77% on every pick including toss-ups (174-79). This headliner is nowhere near that flagged tier. Treat it as the toss-up the model says it is.

A card that doesn't need the comeback to sell it

The UFC is calling UFC 329 its sixth numbered event of the year, and the promotion's "Embedded" series opened fight week with Holloway grilling out for the Fourth of July before flying to Las Vegas, per MMA Junkie. The co-main carries real stakes of its own: Paddy Pimblett (23-4 MMA, 7-1 UFC) meets Benoit Saint Denis (17-3 MMA, 9-3 UFC) months after Pimblett lost his interim-title bid to Gaethje in January.

Pimblett, for his part, has already booked the sequel in his head. "The perfect fight for me would be Conor," he said in a video posted by UFC Europe, per MMA Fighting, floating a McGregor bout at welterweight in Madison Square Garden this November if both men win Saturday. He also conceded who this weekend belongs to. "I'm not going to be the star of the show on this one. Definitely not. Conor is," he said.

There is a backup on standby, too. Lightweight Mauricio Ruffy posted a video, reported by Sherdog, saying he made himself available to step in for either headliner and stepped on the scale at 84.2 kilograms to prove he could make the welterweight limit on short notice.

How to watch

UFC 329 streams on Paramount+, with the card set for Saturday at T-Mobile Arena in Las Vegas, per Sherdog and MMA Junkie. Whatever McGregor is now after 1,827 days away, we will find out live. Our number says lean Holloway and hold it loosely. On a fight this far outside the data, that honesty is the pick.