Andy Ruiz knew he had to change everything about his career if his next boxing relationship was going to work.

The trainer tasked with taking over the reins had to know that Ruiz was willing to go to that extreme before taking him on as a client.

“The question with Andy was always the focus and the discipline,” Eddy Reynoso, Ruiz’s head trainer told in an earlier interview regarding the former unified heavyweight titlist. “He has all of the talent. The most important thing we needed to know before agreeing to work with him is if he’s capable of having that discipline and mentality.”

Ruiz (33-2, 22KOs) has proven to be a star pupil, undergoing a full makeover in his time with the 2019 Trainer of the Year. The work comes ahead of his upcoming all-Mexican heavyweight showdown versus Chris Arreola (38-6-1, 33KOs) as the pair of California natives meet atop a Fox Sports Pay-Per-View event. The matchup—which has been more than a year in the making—takes place this Saturday at Dignity Health Sports Park in Carson, California.

The fight is the first for Ruiz since losing his WBA/IBF/WBO/IBO heavyweight titles to Anthony Joshua in their Dec. 2019 rematch in Diriyah, Saudi Arabia. Ruiz showed up grossly out of shape for the bout, which came six months after the Imperial, California native shocked the world in handing England’s Joshua (24-1, 22KOs) his first career defeat via 7th round knockout in June 2019.

The fall from grace led Ruiz to reach out to Reynoso and his star pupil, pound-for-pound king Saul ‘Canelo’ Alvarez (55-1-2, 37KOs). The two both let the heavyweight know the ground rules up front, which Ruiz has fully embraced. A far slimmer—and more importantly, a more focused—version of the former heavyweight titlist is expected to enter the ring this weekend, the product of months of hard work in order to take that first step towards regaining past glory.

“The most important thing was the discipline and the mentality,” Reynoso noted during a recent media workout. “That is what we’ve been working on. From there, we have the building blocks to work each and every day.

“The talent and the ring intelligence has always been there with him. The discipline was the most important thing. It’s been a pleasure to work with him. We are happy with his progress and commitment.”

Jake Donovan is a senior writer for Twitter: @JakeNDaBox