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When a fight comes to a close, it doesn't take long to ask the inevitable question: What's next?

Floyd Mayweather Jr. is 50-0 and is headed back into retirement, but Conor McGregor is still in his prime as the UFC lightweight champion. However, his performance against Mayweather—a competitive 10th-round TKO loss Saturday night in Las Vegas—leaves options open in the boxing realm.

Steven Rondina, what should McGregor do for his next bout with the "Money Fight" now behind us?

First, here's what MMA Fighting's Ariel Helwani noted:

Steven: McGregor will have been out of UFC competition for over a year by the time he returns to the Octagon.

On the one hand, that's bad due to the noticeable dip in UFC pay-per-view sales and the glut of contenders in the lightweight and featherweight divisions. On the other hand, it's great because there are so many prospective opponents for him.

If I'm in charge, I'm throwing McGregor a softball for his return. While he may have lost to Mayweather, the response to his performance has been resoundingly positive. There will be a lot of curious newcomers watching when McGregor next enters the cage, and it would be silly to put him in a position to lose.

Jeremy Stephens is a perfect opponent. The storyline of looking to get revenge for McGregor's epic diss (link NSFW) last year is easy to sell. While some MMA fans might harrumph about the matchup, it would soar to over one million buys and would end with an impressive victory for McGregor.

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Unfortunately for the entire combat sports world, I'm not in charge of the UFC. Sean Shelby and Dana White are, and they're nothing if not shortsighted with their talent.

They'll put together the biggest fight possible, no matter the risk involved. And the biggest fight possible is a rubber match with Nate Diaz.

Nathan: That's the fight to make.

Any return fight for McGregor will do over a million buys, which has become the benchmark for UFC success. That's the strength of McGregor's name. Still, it's about making the biggest fight possible.

Diaz is that fight, as Pat Muldowney, formerly of Fox Sports, and MMAjunkie's Chamatkar Sandhu tweeted:

Their rematch did 1.65 million buys (h/t MMA Payout), and following McGregor's boxing spectacle with Floyd, it will do no less than two million. No other fight touches that mark.

McGregor talks about money and paydays for a reason. That's where his interest lies. The only other fight that would net him equal, if not more, dead presidents is a boxing tilt against Paulie Malignaggi, but it's not a fight the combat sports world is clamoring for at the moment.

Steven: The McGregor vs. Malignaggi beef started out interesting but lost steam quickly. That said, if McGregor's next fight takes place in a ring (or if Malignaggi is willing to get into the cage), that's the one to make.

While the discussion of training-partner etiquette is lost on most combat sports fans, this is still a bona fide grudge match in a way few fights are. Looking to get revenge against McGregor in the ring is a pay-per-view slam dunk, and so is turning the tables by facing a boxer in the cage.

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Don't get me wrong: I want to see McGregor vs. Diaz III. Their rivalry is one of the greatest in MMA history, and I could see that fight blowing away the UFC PPV buyrate record. But the reward isn't worth the risk.

Of course, McGregor has plenty of suitors past Diaz and Malignaggi. Georges St-Pierre, Tyron Woodley, Max Holloway, Tony Ferguson, Kevin Lee and Khabib Nurmagomedov all make sense. Do any of those tickle your fancy more than the rubber match?

Nathan: No.

I don't want to see McGregor even attempt to cut back to featherweight, and any lightweight or welterweight foe not named Nate Diaz doesn't interest me at this juncture.

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The Malignaggi fight doesn't attract me in the slightest, but considering the economics of a non-MMA bout makes it a possibility. It's not a stretch to imagine Zuffa with its boxing platform in association with McGregor Sports and Entertainment for that fight.

What should come next is simple. Any other opponent besides Diaz, and I'm buying the event simply to watch McGregor. No one else adds value. Diaz adds value and intrigue. That's the fight to make.

Period.