LOS ANGELES — Abner Mares couldn’t hide the disappointment from his face.

He was gearing up for a return bout with Leo Santa Cruz, THE RING’s top featherweight when he received the call: You’ll have to wait.

Santa Cruz’s father and trainer, Jose, petitioned for a stay-busy fight for his son following what would be a nine-month layoff. Al Haymon obliged. Mares conceded. What other choice did he have?

So there Mares was, sitting two seats to the left of Santa Cruz on Tuesday to announce a Fox-televised doubleheader on October 14 in Carson, California, featuring the men in separate bouts. Santa Cruz takes on journeyman Chris Avalos; Mares faces a much-tougher customer in Andres Gutierrez.

“I’d rather be sitting on the other side of this stage,” Mares expressed, though he’ll get his wish in early 2018 if all goes according to plan.

He was — is — ready to fight Santa Cruz in the rematch in October. When they met the first time, in August 2015, Santa Cruz outgunned Mares in a spirited fight to win a decision.

Now, with Robert Garcia in his corner, Mares’ style and effectiveness transformed over 12 rounds against Jesus Cuellar in December. Well, it didn’t truly transform there and then — the hard work was repeated over and over during a one-year period in Oxnard, California.

Mares knew he needed to ditch his brawling ways and box if he was to achieve longevity and return to relevancy. Cuellar was a nice victory for Mares, and he was able to show off some new tools, namely a propensity to box on his toes, utilizing lateral movement and a quick jab.

Now, he wants to exact revenge and prove that he, not Santa Cruz, is the top 126 pounder in the world. He just has to wait.

“I don’t want to sound like an a—— and say ‘hey, I’m fighting the better guy,’ but it is what it is,” Mares said. Gutierrez (35-1-1, 24 KOs) actually was slated to fight Carl Frampton in July when suffered an injury in a freak shower accident. “He’s gotta do his business and I’m sure he is. I got a tough fight in front of me.

” … I hoped it would have been a direct rematch instead of all these so-called tune-up fights where someone can get injured, something can go wrong. Anything can happen. But he chose that and I think he just took a long vacation and felt he wasn’t going to be ready for it.”

But Mares was. And next year, he feels he’ll be in even better position to topple Santa Cruz (33-1-1, 18 KOs). That’s because he now has another fight — another camp — to implement his new style with Garcia. Like a quarterback operating out of a fresh playbook with a new offensive coordinator, the athlete is usually better in Year 3, or in this case, Fight 3.

“I’ve got a new coach, I have a different mindset,” he said. “Just a different time; I’m a more mature now, as a fighter, as a person. I’m 31, people are already asking me about retirement. Man, I’m just getting started.”

Perhaps same Leo, different Abner?

That’s the way Mares sees it playing out. But first, he must play the waiting game, and avoid any stumbles in the process.