It used to be a slam dunk.

Whether it came when he was still an active fighter or in the immediate aftermath of his post-Andre Berto retirement in 2015, Floyd Mayweather Jr. was a guaranteed winner.

When people asked my opinion on possible matchups or dream scenarios, it never changed.

When it came to 21st century welterweight champs, Mayweather would beat them all.

He never fought Vernon Forrest, Cory Spinks, or Antonio Margarito, but he’d have handled them.

And though Shane Mosley and Manny Pacquiao suggested after the fact that there were injuries at play when they did fight him, I never swayed from believing he’d have won at their optimum health, too.

It hadn’t changed much in the subsequent years either.

No matter if it was Keith Thurman, Shawn Porter or Paulie Malignaggi claiming a share of supremacy at a modern-day 147 pounds, they never moved me enough to think that Mayweather couldn’t beat them.

But all of a sudden, there’s a little doubt creeping in.

And the more current welterweight king Terence Crawford makes headlines by saying he’s ready, willing, and able to jump a few rungs to face Canelo Alvarez, the more I wonder what might have occurred had he been at his current level at the same time Floyd was near the peak of his 147-pound powers. 

When pondering such a match, the math alone is staggering.

Mayweather and Crawford are a combined 90-0 with 58 KOs, not to mention legit sanctioning body titles in eight weight classes (5-3 Mayweather), Ring Magazine titles in six weight classes (3-3), and four BWAA Fighter of the Year awards (3-1 Mayweather). 

The “Pretty Boy” turned “Money,” Mayweather reached the International Boxing Hall of Fame in 2021 and “Bud” is a lock to join him soon after the moment he decides to hang up the gloves.

And, to ex-middleweight title challenger Billy Lyell, the scale matters, too.

“I really think at 135, 140, Mayweather wins handily, 8-4-ish,” he told Boxing Scene. “I think Mayweather was more polished and better than Crawford when they were both young professionals. Better defense, more ring generalship, just better.  However, I think Crawford continued to get better as a pro and is completely on Mayweather’s level at 147. I might give him the edge, but maybe not. Really 50-50.”

Mayweather graduated to welterweight after snatching Arturo Gatti’s WBC title at 140 with a six-round evisceration alongside the Atlantic City boardwalk in 2005. He subsequently went 12-for-12 in fights at the 147-pound limit, held all four widely recognized belts at one time or another, and scored three KOs — including two in title fights with Ricky Hatton and Victor Ortiz.

His M.O. was similar in many of the dozen wins: Stay in the pocket, operate from a defensive shell, and potshot frustrated opponents into oblivion while gradually reducing their work rate to a blip.

Crawford, meanwhile, does things a little differently.

He stands the same 5-foot-8 as Mayweather and has a slightly longer reach (74 inches to 72) but comes off as a much more offensive fighter while effectively switching stances. He became a four-belt champ at 140, moved to welterweight in 2018, and has won eight straight title fights since doing so – without a single opponent lasting the distance and only two getting through as many as nine rounds.

An impressive run, to be sure. 

But Jose Benavidez is hardly Pacquiao and Shawn Porter not Mosley.

In other words, let’s pump the brakes, says Randy Gordon.

“I think the boxing mastery of Floyd would have been too much for Crawford,” he told Boxing Scene, “who we may be elevating into a boxing stratosphere he has not reached yet.

“Let’s not put the cart before the horse.”

Indeed, Mayweather mixed a few high-end dalliances into his welterweight run, climbing up a division (though never weighing more than 151 pounds) for title wins over Oscar De La Hoya, Miguel Cotto, and the aforementioned Alvarez, who, at 23, was already 42-0-1 and a two-belt champ.

Crawford’s destruction of Errol Spence Jr. warrants his ascension to the top of today’s ring heap, but the rest of his resume – while pristine – doesn’t have near the heft of Mayweather’s at a similar age. 

But he does look to be leaps and bounds ahead of his brethren, just like Floyd did a few years back.

And given his ability to switch stances and punch with power and carry that prowess deep into fights against opponents of many styles and strengths, could it be enough to pull off the historical feat against a Mayweather who was as successful – but far different – than he’d been at lighter weights?

Maybe? Yes. 

Definitely? No.

Not according to Jim Lampley anyway.

HBO’s ex-blow-by-blow man is as big a Crawford fan as they come and was entrenched in the Nebraskan’s camp before what many labeled a 50-50 fight against Spence, but he’s not willing to take the extra fantastical step to suggest it’s Crawford over Mayweather.

Not because of what Crawford isn’t. 

But because of Floyd is – or was.

“Crawford at 147, the toughest matchup of Floyd’s career and would win some rounds,” he told Boxing Scene. “But truly great defenders almost always beat attackers, so I can’t pick Crawford to win. 

“Mayweather, unanimous decision, is a disappointingly controlled fight.”

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This week’s title-fight schedule:   

No title fights scheduled.

Last week's picks: None 
2023 picks record: 29-11 (72.5 percent)   
Overall picks record: 1,279-419 (75.3 percent)   

NOTE: Fights previewed are only those involving a sanctioning body's full-fledged title-holder – no interim, diamond, silver, etc. Fights for WBA "world championships" are only included if no "super champion" exists in the weight class.   

Lyle Fitzsimmons has covered professional boxing since 1995 and written a weekly column for Boxing Scene since 2008. He is a full voting member of the Boxing Writers Association of America. Reach him at fitzbitz@msn.com or follow him on Twitter – @fitzbitz.