Steve Bunce explains to ESPN what Anthony Joshua needs to do in order to secure a unification fight with Deontay Wilder. (2:37)

As Andy Ruiz was in the final stages of preparation for his April 20 bout against Alexander Dimitrenko, he was asked about the three best heavyweights in the world. If he could pick one of Anthony Joshua, Tyson Fury and Deontay Wilder, whom would he like to face the most?

He answered without hesitation: Anthony Joshua.

"I think he's a perfect match for me," Ruiz said. "Styles make fights. He's high, he doesn't have a lot of head movements, so I think with my speed and pressure, I think it would bother him a lot."

At that time, Jarrell "Big Baby" Miller was scheduled to face Joshua on June 1 at Madison Square Garden in New York.

But on the week of Ruiz-Dimitrenko, it was announced that Miller had failed multiple drug tests. This left organizers with no choice but to come up with a replacement for this show, which had sold a good amount of tickets and has a large contingent of Brits flying over for what is Joshua's American debut.

When Ruiz stopped Dimitrenko in Round 5 on a nationally televised card, he immediately stepped to the forefront of possible opponents.

"After the good performance on April 20 against Dimitrenko, I started harassing [Matchroom Boxing promoter] Eddie Hearn to give me the opportunity ... I could do better than all these guys he has lined up," said Ruiz, who unlike other heavyweights under the Premier Boxing Champions banner, namely Luis Ortiz, was not being lined up for WBC champion Deontay Wilder in the second half of 2019.

"So [Hearn] told me to make some noise, and that's what I did." Within a week and a half, a deal was consummated, and suddenly, Ruiz is making a multimillion-dollar payday. But this opportunity is not just about the money, according to Ruiz.

"I have another chance to [become] the heavyweight champion of the world and the first Mexican heavyweight champion of the world -- and make history," Ruiz said, who lost a title shot by majority decision against Joseph Parker in 2016. "I think that's the major lottery, right there."

Perhaps he can thank Ortiz and his team for having the winning ticket and deciding not to turn it in.

"I was so surprised," Ruiz said of Ortiz's decision to bypass Hearn's offer to fill in for Miller. "But things happen for a reason, and they chose me for a reason. So I'm really happy."

Ruiz possesses rare fluidity and hand speed for a heavyweight and has never really been hurt in a fight. However, Ruiz has been questioned regarding his overall dedication and commitment to the sport. It's why in the past he has been a bit too rotund. The 29-year-old Ruiz still has a baby face and, not ideal for boxer, carries additional weight.

Andy Ruiz Jr., right, told Matchroom promoter Eddie Hearn he wanted the fight against Anthony Joshua after the original opponent, Jarrell "Big Baby" Miller, had failed multiple drug tests. Ed Mulholland/Matchroom Boxing USA

Ruiz says much of those long stretches away from the gym were caused by his issues with Top Rank, his original promoter, which he says muted his motivation for the sport. His outlook toward boxing has changed, and just as importantly, the quick turnaround from April 20 is something his camp thinks is beneficial for his preparation for Joshua.

Ruiz says he took only one week off after his last fight before getting back into the gym.

"I feel sharp, I feel alert, I feel good," he said. "My weight is good, my body feels good. So I'm ready for June 1, whatever happens." He said he expects to weigh in the mid-250s for this fight.

Manuel Robles Jr., who trains Ruiz, said that after having their best camp for Dimitrenko, going right back into battle is ideal.

"Having five weeks to prepare for Joshua doesn't seem like a whole lot," Robles said. "But you've got to consider we haven't stopped for 10 weeks, and then getting a tune-up fight, it feels great."

During a training session at Legendz Boxing Gym in Norwalk, California, Ruiz spent most of the time concentrating on head movement and slipping punches. For Ruiz, being able to nullify Joshua's long telephone pole jab will be vital. If he can't, he'll be stuck on the outside of it all night. But if he's successful in evading it, he'll have a chance to get inside the range where he can let his hands go.

"It's no secret. We've got to take the distance away from Joshua, with him being the taller man with the longer reach," Robles said. "We have to fight inside. We have to go look for the fight."