There’s a working theory that Saul “Canelo” Alvarez is sloping down the back side of his career, with the premise being that he will turn 34 this summer, has a loss and three unanimous decision wins (including two in which he appeared to fade) in his past four fights, and he has avoided his most serious challenger.

As Mexico’s Alvarez (60-2-2, 39 KOs) nears his May 4 undisputed super middleweight title defense versus his countryman and former junior middleweight champion Jaime Munguia (43-0, 34 KOs) of Tijuana, the doubters will watch closely.

On Friday’s episode of ProBox TV’s “Deep Waters,” analyst and former 140-pound world champion Chris Algieri said Alvarez has strayed into a conversation that has been reached by every fighter, inculding all the greats of the past.

“We’re always talking about ‘Father Time’ – age – and we’re talking about the time when Canelo’s going to be overtaken,” Algieri said.

“We never know which version of Canelo’s going to show up, but in terms of trends, we’ve got Munguia on the way up and we’ve got Canelo going down. Are they going to intersect at a time where Munguia can get the victory? That’s really the question. And it’s not something we’ll know until fight night.”

Logic – and the bookmakers who list Canelo as a -550 favorite – say Alvarez is going to rely on his power, ring IQ, experience and skill advantages to defeat his younger countryman, who has moved up in weight and is elevating to a grand promotion for the first time.

Thanks to the luxury of his standing as "The Face of Boxing,” Alvarez is entitled to decide his path, and while some fans and critics flamed when he chose Munguia over the more deserving unbeaten former super middleweight champion David Benavidez, Alvarez is positioned to again delay Benavidez by meeting a now-mandatory title challenger in heavy-handed Edgar Berlanga.

Or perhaps Alvarez’s future will be decided by Munguia.

Munguia is six years younger and has participated in 285 fewer professional rounds than Alvarez as he ascends to the fight of his life.

“I’ve had a funny feeling about this fight, in terms of Munguia’s chances, for a while now,” Algieri said. “I’m a big proponent of Canelo Alvarez and what he’s been able to do in the ring.

“I don’t know, though. I’ve got a feeling about Munguia and his preparation. You mention the things that give Canelo trouble – [punching] output and he’s had trouble with bigger, taller guys [like light heavyweight champion Dmitry] Bivol. Munguia is the biggest 168-pounder I’ve seen in a long time, and he’s improving, he’s developed a right hand and he used his left hook against John Ryder.”

While the 6-foot Munguia finished England’s Ryder by ninth-round TKO in January, the 5-foot-8 Alvarez went the distance with Ryder and seemed to tire in the final half of the bout in his Mexico homecoming bout last May.

“So there’s a lot of underlying reasons I’ve been listening to and seeing, and Munguia’s a very, very live dog.”