If you didn’t know any better, you’d think Juan Diaz was a cinch to avenge his loss to Juan Manuel Marquez when the two get together again July 31 at Mandalay Bay in Las Vegas. After all, Diaz is but 26 years old, which qualifies as something close to pre-pubescent in this era when we start thinking a guy should retire when he’s closing in on 40.

Marquez is 10 years older than Diaz, has a lot of hard miles on him and, on one of the last occasions we saw him, he was sipping urine, of all things, with hopes it would save him against Floyd Mayweather Jr.

It didn’t.

That was nearly a year ago, and despite the lessons taught to us by George Foreman, Bernard Hopkins and a few other golden oldies, 36-year-old fighters generally do not improve. The best they can hope to do is maintain and hope that the smarts they’ve acquired will pull them through.

One can make the case, however, that it is Diaz who is closer to being burned out than Marquez, despite the 10 years that separate them.

Diaz is what is known in fight game parlance as a volume puncher, which means his strength lies not in out-maneuvering his opponent or knocking him unconscious, but in out-working him – overwhelming him with punches.

History tells us fighters of that type tend to burn out at a young age.

Jeff Fenech, who won titles in three divisions and couldn’t fight a lick anymore at just 29 years old, is a good example. Ricky Hatton may be another. Ray Mancini was done at 24.

Wayne McCullough will argue that it was the British Boxing Board of Control that ended his days as a top guy when they suspended him for what eventually were found to be questionable medical causes. But I believe he posed no threat to top fighters anymore after Erik Morales beat him in 1999, when “The Pocket Rocket” was just 29.

It may be that Diaz (35-3, 17 knockouts) peaked around the time he bludgeoned Acelino Freitas and Julio Diaz in 2007. His record after the Diaz fight is 2-3 with losses to Nate Campbell (L 12), Marquez (KO by 9) and Paulie Malignaggi (L 12).

The wins? A controversial decision over Malignaggi (W 12) in Texas in their first fight and an admittedly strong performance against slugger Michael Katsidis (W 12).

To me that looks like a guy who might be burned out. So I called Diaz’s long-time trainer, Ronnie Shields, who’s a straight shooter.

Shields told me that while he agrees completely that volume punchers like Diaz burn out young, that’s not the case with his fighter.

“Not at all. He’s not burned out,” Shields said. “And he realizes one thing: That if he doesn’t win this fight, there’s a chance his career could be over. He don’t want that.”

Shields said Diaz has been looking very good in the gym and that they have a different game plan in store for Marquez this time.

“He knows we can’t fight the same fight we did last time. We’re taking a couple different approaches,” said Shields. “Juan has to continue to use his jab. He can’t punch and just stay in front of the guy like he did last time. Juan just wanted to overpower him. He knows he’s not a power puncher, but a volume puncher can get away with things like that — but not against a guy like Marquez.

“It’s OK to be a volume puncher, but you’ve got to pick your spots. And that’s what we’re going to do.”

I tried another guy I respect, longtime Texas-based manager Lester Bedford, who has been watching Diaz from the time he started out. Bedford isn’t sure whether “The Baby Bull” shows signs yet of burnout. He said Marquez (50-5-1, 37 KOs), will show us.

“I think we’ll know better after this fight where’s he at,” Bedford said. “The Malignaggi fight was just a horrible style for him, and if I had been representing him that’s a fight, I would have stayed away from (Malignaggi) because of the styles.

“But Marquez is going to be there to be hit, just like he was last time. And Marquez is not going to be better than he was last time. But there’s a possibility Diaz may not be either. Both of them may have slipped backwards just a little bit.”

Bedford said Diaz needs a good win to restore his reputation and, more important, his confidence. He told me how he regretted bringing Jesse James Leija back against Azumah Nelson right after Lejia had been stopped by Oscar De La Hoya. Nelson stopped Leija in the sixth round.

“They really need to get themselves back into a rhythm and work themselves back into condition against lesser competition and build their confidence,” Bedford said. “I don’t know what Diaz’s confidence is going to be like after getting stopped by Marquez and then getting shut out by Malignaggi. I don’t know where he is mentally. When guys come off losses like that and they’re young, you can destroy their confidence. As soon as the Marquez fight was over, I would have gotten him three or four wins. Sometimes you got to drop a guy back to Triple-A so he can get back his swing.

“There’s no way Marquez is going to be a better fighter, but it’s a tough fight to come back to for Diaz.”

I don’t believe Shields is worried about Diaz’s confidence. But it’s hard not to read into what he said before we ended our conversation.

Shields told me, “If he loses this fight, I would rather see him quit than just be used as a name. Just say, ‘I’ve had a great career’ and call it quits. I don’t want Juan to be a pawn for nobody. He’s too good of a fighter for that and too good of a person for that.”

Typically, trainers, like fighters, are loathe to discuss defeat so close to a big fight. It’s an unspoken rule in the business that two subjects are never broached: losing and dying in the ring.

If Diaz’s time has indeed come and gone, even at the tender age of 26, our wish should mirror Shields’. The kid has done enough.

Some random observations from last week:

Note to Nonito Donaire: It’s easy to “experiment” when you’re fighting a guy that would fit right in on the set of “Little People Big World.” Next time, do us a favor and save it for the gym. ÔǪ

About five years ago, when I was working on a book with Joe Frazier, I spent some time with Mike Jones in Frazier’s gym in Philadelphia. It felt so good to be in a gym again I almost asked Jones to spar a couple rounds with me. Looking back on it, I’m glad I didn’t; the resultant brain damage would have made it difficult to finish the book — or count to five. Still, am I the only one who feels as if Jones throws a lot of arm punches? ÔǪ

Kudos to Lanardo Tyner for outlasting and stopping Antwone Smith in a brawl. How about Jones-Tyner if Jones can’t get Andre Berto? If Jones were promoted by anyone other than J Russell Peltz, I’d say it will never happen; too much to lose for Jones, not enough to gain. But Peltz, one of the last, great old-school promoters, has never coddled his guys. How about it, Russell? ÔǪ

If you heard the most recent episode of Ring Theory , you know I picked Bernabe Concepcion to last the distance with Juan Manuel Lopez. As it happens, Lopez’s exciting second-round knockout pulled Eric Raskin even with me in our Quick Picks competition. Thanks for nothing, Bernabe. ÔǪ

My embarrassing and entirely inexplicable obsession with boxing means I wouldn’t know LeBron James if I tripped over him. What sport does he play again? ÔǪ

Yes, John Molina gets credit for the way he came back to stop Hank Lundy, but he looked god-awful for the first 10 rounds, didn’t he? And Lundy isn’t exactly Pernell Whitaker. ÔǪ

Doesn’t Molina look like 1980s lightweight belt holder
Harry Arroyo?. 

Speaking of look-alikes, Opie Taylor doppelganger Saul Alvarez stopped Luciano Cuello Saturday night in Mexico (on wbctv.com, if you can stand it). If it’s handled right, and if Golden Boy Promotions and Top Rank can get past their insufferable squabbling, give it two years and Alvarez against Julio Cesar Chavez Jr. will be a blockbuster. ÔǪ

Was it just me or did Matt Godfrey do a pretty good job in the studio on Friday Night Fights? 

Sure it’s an abomination that it’s on pay-per-view, but Shane Mosley-Sergio Mora is interesting. Mosley looked about 140 years old against Floyd Mayweather, but Mayweather does that to everybody. And Mora is fast and energetic. What’s not to like? ÔǪ

John Duddy, Kevin McBride and Joey McCreedy all got their heads handed to them recently. Thank goodness Billy Conn isn’t around to see this. ÔǪ

If you’re looking for a smart, entertaining, and horrifying read this summer, check out THE RING columnist Ivan Goldman’s latest book,
EXIT BLUE a taut, funny, political satire. It’s Goldman at his best, which is quite good indeed.

Bill Dettloff, THE RING magazine’s Senior Writer, is the co-author, along with Joe Frazier, of “Box Like the Pros.” He is currently working on a biography of Ezzard Charles. Bill can be contacted at [email protected]