Former heavyweight unified world titlist Andy Ruiz Jr. returns to the ring Saturday for the first time since losing his belt in a rematch against Anthony Joshua in December 2019 to face former title challenger Chris Arreola. The fight is scheduled for 12 rounds at Dignity Health Sports Park in Carson, California.

Ruiz (33-2, 22 KOs), 31, of Imperial, California, scored a big upset in June 2019 by stopping Joshua in the seventh round to win the WBA, WBO and IBF world titles. He lost the rematch six months later, and he hasn’t fought since.

After the loss, Ruiz parted ways with trainer Manny Robles and now trains with Eddy Reynoso and Team Canelo Alvarez in San Diego. Ruiz has lost weight and seems ready to resume his pursuit of reclaiming his titles — but first, he must fight Arreola.

Arreola (38-6-1, 33 KOs), 40, of Los Angeles, lost his three world title fight opportunities — against Vitali Klitschko, Bermane Stiverne and Deontay Wilder. After winning two consecutive fights, Arreola’s most recent fight resulted in a wide decision to Adam Kownacki in August 2019.

ESPN asked a panel of boxing insiders, as well as former opponents, for their takes on Saturday’s fight.

Editor’s note: Responses have been edited for clarity and brevity.

Timothy Bradley Jr., ESPN boxing analyst, former junior welterweight and welterweight world titlist

How Ruiz wins: Andy Ruiz just gotta be himself. He’s just gotta be who he is. Be that great, fast-twitch counterpuncher that he is. He should have no problem beating up Chris Arreola. Arreola is an old vet, 40 years old, maybe semiretired. He hasn’t fought in about 19 months, and then before that, he has had long layoffs. I mean, this guy has one foot out the door. But he’s always very tough, very durable — he can take a good shot. He will be there to apply pressure and be right in front of Andy Ruiz. As for Ruiz, all he has to do is be the slick counterpuncher, use his speed and I think he can stop Arreola.

Ruiz can win this fight in several different ways. He can use his feet, he can move, he can set counters, he can look beautiful in this fight. And he’s under the guidance of trainer Eddy Reynoso in the Canelo camp now, so you know he’s gonna bring some flair into the ring with those fast hands. And you know he’s gonna bring his power and he’s going to be very creative with his offense. And just remember what I say, watch these two punches: that left hook and that right uppercut from Andy Ruiz. I think those two punches are gonna be deadly.

How Arreola wins: Chris needs a miracle. I mean, he needs to try to knock out Ruiz. He needs to just push the pace, be who is, because there’s no other way. Chris Arreola is no boxer. He’s not going to use his legs and move; he’s going to be directly in front of you, trying to outwork you, trying to pound you — he’s a bruiser-type fighter. You got the bruiser-type running back in football, that’s Arreola. He’ll take your best and say, “Hey, can you take my best?”

So, he gotta try to knock out or hurt Ruiz and try to finish him. The only way he wins this fight is by knockout — that’s the only way he wins this fight.

X factor: It’s going to be the fact that Ruiz is now with trainer Eddy Reynoso and the culture in that gym. Reynoso has done a brilliant job with Oscar Valdez; he’s done a brilliant job with Canelo Alvarez; he’s done a brilliant job with Ryan Garcia; he’s really showing what type of quality trainer he is. If you look at his fighters, they’re not just straightforward fighters; these guys they adapted, they understand the sweet science of boxing — hit and don’t get hit. I just think it’s brilliant what he’s doing, and I think looking at the camp with Ruiz and seeing what he’s been doing and how, his body started to harden up a bit. I don’t know if those pictures they post on social media are photoshopped or not, but Ruiz looks good. He looks in shape, looks focused, and it looks like he’s going to be, again, a force to be reckoned with in this heavyweight division. That camp is doing something special over here, so you could say that camp will be key.

Prediction: Ruiz is going to land the more effective blows; he’s going to land the crisper, more effective punches than Arreola. Arreola will have the volume, but he’s going to take a lot back. There’s gonna be a lot of opportunities for counters for a quick-fisted fighter like Ruiz, so if Ruiz looks like I’m expecting him to look, I think it’s a possibility he can get Arreola in Round 8 or Round 9.

But trust me, it’s gonna be one hell of a fight. It’s gonna be so entertaining because Arreola always comes to fight.

Sergio Mora, DAZN boxing analyst, former junior middleweight world titlist

How Ruiz wins: If this fight happened maybe five years ago, I would’ve said Arreola was going to win and that it would’ve been a tough fight for Andy Ruiz. But at 40 years old now, and having lost three attempts to win the title, I don’t see Arreola having a chance. And Ruiz’s hand speed is incredible — I’ve seen it up close. For a big man, he has fast hands and they come off really sharp, counterpunching-wise, so I just think Arreola is tailor-made for the speed of Ruiz. Ruiz is very motivated, training with Canelo Alvarez and training with Eddy Reynoso, and he wants to prove what he’s learned.

How Arreola wins: He needs to take the best shots from Ruiz, and I really mean that. That’s the only way I could see him win. Take the biggest shots, and if they don’t hurt him, don’t put him down, and Arreola can actually weather the storm and back up Ruiz. That’s something Ruiz is not used to. And Arreola can back up bigger men; we’ve seen that. He’s gonna have to do that and then use that experience, fight inside to make it a real fight. Get out of the first three rounds, and be accurate and get into the fifth, sixth round and make it a rough fight and stand a chance, but Arreola’s going to take a lot of punches trying to get inside.

X factor: Motivation — and the fact that Ruiz has so much to prove. He got a reality check losing his titles and then everyone turning on him. We saw the ugly side of the sport: No matter how much money you made, no matter how many millions, Ruiz turned the sport of boxing upside down in the wrong way, and he pissed a lot of people off without showing the grit and determination of a champion in the rematch with Joshua. So, Ruiz has to prove a lot of people wrong, and I think that motivation, for a fighter, is key. He needs to show his character, and I think Ruiz learned his lesson. He got kicked in the mouth, and now he’s trying to prove that he can still do something really big.

Prediction: Ruiz is motivated by greatness now, so, yeah. Like I said, if this was five years ago I could see it being a good old all-action fight. But because it’s now, and we’re dealing with a 40-year-old Arreola, who still loves to fight — don’t get me wrong — I don’t see this fight going into the middle to late rounds. I don’t see it going past the eighth or ninth round. Andy Ruiz’s hands are too fast.

Raul Marquez, former U.S. Olympian and junior middleweight champion, Showtime boxing analyst

How Ruiz wins: Ruiz is going to have to mix it up. He’s younger, faster, and now that he’s with trainer Eddy Reynoso, he’s been practicing a lot of his boxing skills with Canelo Alvarez, somehow imitating Canelo’s style. He’s doing a lot of that, so I think it’s going to be a little bit of both — be a boxer, puncher, mix it up, break down Arreola with some good body attack, wear down the old warrior. The only thing I’m concerned with is Ruiz’s new body. Ruiz is known as being a big guy and he’s been successful as a fat boy. With this new physique, whatever he’s doing, it’s a tremendous change. I mean, he’s never looked that way, and I don’t know if his body is going to hold up in the later rounds because he’s never been that type of guy that has a body like that. I’m curious to see how the new training regimen is going to hold up late in the fight. You don’t win fights because of your body; you win fights because of your skills. The whole time in his career, he’s been the big guy, or whatever you want to call it, but he won the heavyweight title like that. He’s been successful like that, so I’m curious to see how this is gonna turn up in the later rounds.

How Arreola wins: Just go in there and try to make a statement. And what I mean by that is let Ruiz know that you know this is your last shot, that you know that this is it for you and you will do anything to win. Arreola has been around; he’s got a lot of experience and has been in fights with Vitali Klitschko, Deontay Wilder, Bermane Stiverne — he’s been there with the best, right, so use that experience. That’s the only thing I have for Arreola to win: Don’t give Ruiz any respect. I would take it to him and try to take him into deep waters, try to break him down to let him know that “Hey, I still got it, still got something left in the tank.”

X factor: I would say Ruiz’s improvement with defense. What I’ve seen on videos, not getting hit as much using the rolling-the-shoulder thing like Canelo. I was looking at some video where he’s trying to imitate Canelo and he kind of rolls with the punches and then comes back. So, his defense could be the difference in the fight.

Prediction: I’m still gonna go with the younger guy, Ruiz. He has more speed — he’s got a lot more left in the tank. He’s only lost to Anthony Joshua, and I think he stops Arreola in eight or nine rounds.

Travis Kauffman, former heavyweight contender, fought Chris Arreola in 2015

How Ruiz wins: It’s going to be an exciting fight, but I think it could have been a lot more exciting five of six or seven years ago, when Arreola was younger and at his prime and didn’t have so many wars in the ring. I still think it’s going to be exciting, but I don’t think it’s going more than a few rounds. Chris is a personal friend of mine, and I know that in the heavyweight division, one punch can change it all. But I just think Ruiz is too young, too hungry, and he’s extremely fast. I like Ruiz and I just think he will overwhelm Arreola, just because of the fact that Chris is older and has been through a few wars in the ring.

How Arreola wins: He has to knock Ruiz out. But let’s be real: Ruiz has never been knocked out. He’s been down a couple of times, but none was devastating. I don’t see Chris knocking him out. I see Ruiz powerhousing Chris. I’m the only fighter ever to back up Chris Arreola and this is the same thing, except Ruiz is a little younger than I was. It was my first time under the big lights, and when I dropped Chris in the third round, I should have come to him and finished him, but I was more concerned with the fact it was my first big fight and I wanted to make sure I lasted the full 12 rounds. I don’t see Ruiz taking those chances at all, and as soon as he’s able to hurt Chris, he will be able to finish him.

X factor: His corner. Chris is a fighter. It’s hard to get him out of there. So, his team needs to know when to stop the fight. His team has to step in and say enough is enough. Yes, I know that’s the worst, but the reality is, being a good friend of mine, I want to see him do much more. He’s tough, but he’s not the same fighter he was seven years ago — he’s not the same fighter he was three years ago.

Prediction: Ruiz within four rounds. Like I said, Chris is a personal friend of mine, so I hope that doesn’t happen. But I just think Ruiz is very hungry. He knows he blew his opportunity in the second Joshua fight, and I don’t think he’s going to blow this chance against Chris, because if you lose to Chris, where does that put Andy Ruiz?

Manuel Quezada, former heavyweight contender, fought Chris Arreola in 2010 and Andy Ruiz Jr. in 2014

How Ruiz wins: Ruiz has to stay busy. Arreola is a little on the downside of his career. Ruiz has to stay busy and keep his hands going, go down to the body. If it was me, that’s what I would do, and I believe that’s what Ruiz will do — he’s gonna stay really busy. He was already a busy fighter, and it seems at this time that he’s in real good shape, so I’m expecting him to really put it on Arreola.

How Arreola wins: He just has to really dig deep and then just do what he does best, make it a brawl. Just get out there and make it brawl and make Ruiz fight. I think that’s the only chance he is gonna have, really, ’cause like I said, Ruiz is a lot younger than he is now and he’s a busier fighter. Even though Arreola had a good fight with Adam Kownacki and he was pretty busy in that fight, I think Ruiz is on a different level than Kownacki.

X factor: People say that with the new trainer, Ruiz is more motivated, but I don’t buy into that. It’s about him. If he would have been as disciplined and motivated the way he is now, with any of the trainers he’s had in the past, he would be doing the same thing. Ruiz is a very good fighter. He can be great if he stays motivated; he’s been great from the start, but he needs to be motivated for himself.

Prediction: Oh, man. Arreola and I are really good friends, I just went to Van Nuys (in Los Angeles) to see him train at the Joe Goossen Gym because we are very good friends outside of the ring. So, I went up there and visited him and I wished him the best, but I just think it’s Ruiz’s time, and I think Ruiz is gonna be too much for Arreola. I’m really pulling for Chris and I really wish he would pull it off, but let’s be real. I don’t think this fight goes long. I’m hoping he puts on a great show, but I’m picking Ruiz in an early stoppage. I’ll be surprised if it goes past six rounds.