Andy Ruiz Jr. has heard all the fat jokes, and understands he has a reputation to rehabilitate.

The former heavyweight champion also knows his comeback fight Saturday night against 40-year-old Chris Arreola has been criticized both for the quality of opponent and the price fans will have to pay to watch it.

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But entertainment is entertainment. And Ruiz promises there will be plenty of action on the pre-Cinco de Mayo weekend as he takes his first baby steps toward regaining the title he so unexpectedly won in a stunning stoppage of Anthony Joshua two years ago.

Yes, he was 310 pounds when he began training camp. But for $49.95 those watching at home can tune in to see just how serious Ruiz is about becoming a force in the heavyweight division again.

"It’s going to be an all action fight,"’ the first heavyweight champion of Mexican heritage said. "All the Mexican fans are going to come and support us. The best way to watch this fight is being at home, watching on TV and celebrating."

Just how much there is to celebrate is debatable, considering Arreola is not exactly a prime-time opponent. But comebacks have to start somewhere, and this one will start in a pay-per-view against an aging fighter who is rugged and throws plenty of punches — but has won only two fights in five years and has had weight issues of his own.

It wouldn’t be a proper comeback, of course, if it didn’t come with a back story of redemption and renewal. Ruiz has that and more, including a new trainer and his engaging tale of what happened when he suddenly became the heavyweight champion of the world before and discovered he wasn’t quite ready for prime time.

"I killed the old Andy and a new Andy was born," Ruiz said. "I have a lot to prove. I let a lot of people down, and that’s why I had to make big changes to myself. I know what I’m capable of doing and I know what I can accomplish. I have it inside of me to become the Mexican two-time heavyweight champion of the world."

The biggest mistake, according to Ruiz, is that he let the heavyweight championship get to his head. Hard to blame Ruiz for that, because few gave him a chance when he shocked everyone in boxing by stopping the previously undefeated British champion at Madison Square Garden.

The scale at the rematch in December in Saudi Arabia told the tale better than anything. Ruiz weighed a whopping 283.5 pounds for the fight, and his lack of conditioning and desire were both evident in dropping a lopsided decision to Joshua to lose the title in his first defense.

Now Ruiz has a new trainer, is some 60 pounds lighter than when he began training for Arreola, and has a new perspective on what it means to be a champion. He'll meet Arreola in a scheduled 12-round fight from the Dignity Health Sports Park in Carson, California, where a limited number of fans will be allowed because of pandemic restrictions.

"I didn’t know what was coming my way. I didn’t know what to expect,’’ he said about winning the title. "At the time I had cousins that I didn’t even know, I had uncles and friends from a long time ago I didn’t know until I won. So I kind of went with the flow and that was kind of my distraction. But we all learn from our mistakes. And I’ve got to start all over again, start back at the bottom of the ladder."

Ruiz isn’t exactly at the bottom, but he’s got a ways to go before reaching the top again. Joshua has moved on and is planning to fight two bouts against Tyson Fury this year, though they haven’t been finalized, and the path to another heavyweight championship isn’t exactly wide open.

But Ruiz says he’s motivated now to win back what he once had, and has hooked up with Eddy Reynoso, the trainer of Canelo Alvarez, to help him stay disciplined. He also says he’s learned a lot from being around Alvarez, widely considered to be the top pound-for-pound fighter in the world.

But the 31-year-old had to learn a bit about himself, too. The partying had to go, and the overeating had to stop before he could be comfortable again in the ring.

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"The main thing is we’re learning discipline and that’s something you cannot buy into," he said. "That’s something you have to learn on your own and you have to want it. Discipline is the main thing plus the fundamentals that we’ve been working on that include moving once I lost some weight. Little by little, I started learning new ability that I probably had but now I’m using."

Ruiz plans to fight again in December if he is successful against Arreola and eventually fight for the title again. He also wants to show fans he deserves his place among the heavyweight elite, despite his lackluster fight with Joshua his last time out.

"At the end of the day things happen for a reason and I learn from my mistakes," he said. "So I think I’m in a way better place."