Chael Sonnen warns Conor McGregor faces a steep cardio and comeback test at UFC 329

Conor McGregor’s UFC 329 comeback has attracted a skeptical eye from former middleweight title challenger Chael Sonnen, who framed the assignment as more than just a tough matchup. Sonnen’s concern centered on whether McGregor can handle the physiological and strategic demands of fighting again after an extended layoff, especially in a bout designed for a five-round pace.

McGregor enters UFC 329 as a returning UFC veteran set to rematch Max Holloway in the welterweight main event at T-Mobile Arena in Las Vegas. The fight, according to the reporting, will air on Paramount+. It will mark McGregor’s first fight back after a five-year gap, and he is coming off the kind of career-altering break that ended his last active run in July 2021.

Sonnen’s critique went beyond inactivity. He pointed to McGregor’s history of slowing down during fights and argued that the combination of an extended period away from competition and the early requirement to cover five rounds creates a problem that is not easily solved by preparation alone. In Sonnen’s view, the lack of recent full-camp, in-cage minutes raises the risk that the bout’s later stages will arrive faster than McGregor expects.

In comments reported by MMA Junkie, Sonnen also referenced McGregor’s most recent leg injury as among the worst he has ever seen, while emphasizing that the comeback is happening at a weight class outside McGregor’s prime window. Sonnen tied that to a broader pattern he has observed in combat sports, arguing that moving away from what a fighter’s body is built to do has historically produced unfavorable outcomes.

Sonnen further questioned details around the training camp logistics, noting that he had seen McGregor in a filmed setting outside Ireland and saying he was skeptical about the broader picture. He stopped short of suggesting McGregor will fail to show up, and he expressed confidence that McGregor would make the walk, but he maintained that certain parts of the task appear “insurmountable” at this stage of a return.

The matchup itself carries its own context. Holloway, as described in the lead-up coverage, is coming from a recent stretch of high-level performances inside the Octagon, and Sonnen’s framing implies that Holloway will pressure McGregor early and test whether his endurance and rhythm can hold through the later rounds.

With UFC 329 underway, the clearest watch points are how McGregor starts, whether he can sustain output when the fight stretches into the middle phases, and whether Holloway can keep pressing in the places Sonnen suggested are most vulnerable. The night will also provide an immediate answer to a central question for the welterweight picture: how much of McGregor’s elite skill set translates when the conditioning timeline is compressed by a long layoff.