To borrow a phrase from former UFC heavyweight champion Brock Lesnar, UFC 189 has been in “chicken salad” mode for more than a week now.

From the moment reports surfaced that featherweight champion Jose Aldo had broken a rib during the final stages of his training camp, our hopes for an epic clash with Conor McGregor on July 11 began to dim. On Tuesday, we learned for sure that Aldo was out and Chad Mendes was in against McGregor, with an interim title on the line.

Considering the regrettable circumstances, this was about as good as matchmakers were going to do. And hey, it’s still pretty good.

Better, in fact, than seeing McGregor take on some lesser, hobbled version of Aldo.

Mendes will at least give the 26-year-old Irish phenom a taste of what competition is like at the elite levels of the UFC 145-pound division. Once this bout is over, we’ll likely have a much better idea if McGregor is anywhere near as good as he says he is. That’s something critics have been calling for since his UFC career began during the spring of 2013.

For his part, McGregor is not impressed, either by the current titlist’s decision to pull out or by his new opponent.

“I think Chad Mendes is a substitute, the B level,” he said, during a hastily organized conference call on Wednesday afternoon, via Bleacher Report’s Scott Harris. “He’s a wrestler with an overhand…It’s the McGregor division now.”

At the very least, you have to admire his optimism.

From early in his Octagon tenure, McGregor has been a special case. His natural charisma, effortless gift of gab and strong Irish following have made him nothing short of a revelation in the new UFC landscape, where bankable stars are suddenly few and far between.

Make no mistake, he hasn’t been too shabby inside the cage either. McGregor has done everything UFC brass has asked him to do so far—streaking to a 5-0 promotional record with four TKO finishes.

Yet his competition hasn’t exactly been championship level. At best, McGregor has jetted past a group of tough but unremarkable featherweight journeymen. At worst, he’s beaten up a bunch of carefully selected opponents, who all got the call because Zuffa executives believed they would make him look good.

How you feel about the work he’s done in the Octagon probably says more about how you feel about that matchmaking strategy and UFC ownership in general than what we actually know about McGregor as a fighter.

Fact is, we have no idea what he’s capable of just yet.

Obviously, it was McGregor’s marketability that truly paved the way to his title shot. The UFC looked at him in his designer suits, looked at Aldo’s six-year reign of terror at featherweight and saw dollar signs at the prospect of putting them together. Once the bout was on the docket, the two fighters did their part, engaging in a contentious feud painstakingly chronicled in what felt like a dozen UFC-produced documentaries.

Even as we thoroughly came to know McGregor’s penchant for getting under Aldo’s skin, however, his overall fitness as No. 1 contender remained a mystery. There was simply no way to look at him pummeling Dustin Poirier or getting taken down by Denis Siver and know how he was going to do against the greatest 145-pounder the world has ever known.

Now we’re going to have to wait a little longer to find out.

As far as litmus tests go, though, they don’t get much tougher than Mendes. The Team Alpha Male product comes into this fight on short notice but also as a fully known, universally accepted member of the featherweight elite. He’s 17-2 and his own UFC/WEC resume dates back more than five years. Both of his career losses are to Aldo, and he enters this fight just three months removed from stomping through former top contender Ricardo Lamas in two minutes, 45 seconds.

Mendes also arguably represents a tougher matchup of styles for McGregor than even Aldo. The champion was going to be a colossal leap up in quality of competition for McGregor, but at least his standup-oriented skill set would play to the challenger’s strengths.

Mendes is the exact opposite. He’s a lifelong grappler with typically impeccable cardio, explosive takedowns and the ability to end a fight once he gets it to the mat. McGregor has never fought anyone even remotely like him during his UFC run, either in terms of physical attributes or overall ability.

Mendes is fully aware of that fact, too, as he told Fox Sports’ Damon Martin earlier this week:

I see myself beating this guy three ways. I’m either going to knock him unconscious because he drops his hands a ton and gets lazy in there. I’m going to take him down and submit him because he gives up. Or I’m going to have him on his back crying for his mama for five five-minute rounds, beating the crap out of him. I’m good with all three of them.

As of this writing, Mendes is going off as a slight underdog, according to Odds Shark. Hard not to believe that stems partly from his status as a late-notice replacement and partly from the hype surrounding McGregor. If you stripped away the Irishman’s instant celebrity, surely Mendes would be the favorite, perhaps even by a prohibitive margin.

If McGregor can pass this test, there will be very little to nitpick about him. He’ll have fully made his bones in the 145-pound division and proved he hasn’t just been blowing smoke throughout his UFC career. That alone might be the most surprising outcome of all.

If Mendes beats him? It wouldn’t be a career-ending disaster, but for the time being it would validate critics who said he’d been prematurely boosted into a title shot. It would mean he’d have to win another fight or two before we even started to take him seriously again.

Either way, this weekend figures to provide some definitive answers on how to feel about McGregor moving forward.

That’s likely a lot better than we would’ve done had an injured Aldo stayed in the fight.

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