LAS VEGAS – Freddie Roach recognizes that not everyone is as convinced Callum Walsh will become a junior middleweight world champion as the Hall-of-Fame trainer.

After what Roach witnessed during Walsh’s latest training camp, however, he senses that the strong Irish southpaw is prepared to convert doubters into supporters Saturday night at Allegiant Stadium.

Walsh will face Fernando Vargas Jr. in Netflix’s 10-round co-feature before undisputed super middleweight champion Canelo Alvarez defends his titles against fellow four-division belt-holder Terence Crawford.

Vargas (17-0, 15 KOs) is just the second undefeated opponent of Walsh’s career and his first since he knocked out Luis Garcia (then 3-0) in the first round of his third professional fight.

“This is a great test for Callum,” Roach told The Ring. “Vargas is in his prime and undefeated, so it is definitely a step up for Callum. Callum has faced solid competition. That experience will be to Callum’s advantage for this fight. … Callum’s star is rising and if he fights the way we think he will, then this will be a breakout performance for him.”

Las Vegas’ Vargas, the 28-year-old son of the former junior middleweight champ who trains him, is equally eager to prove himself against the best opponent of his four-year pro career.

“Vargas is a real fighter with a very good jab,” Roach said. “We have studied his fight tapes, and I think we have a solid game plan for him.”

Roach wants Walsh (14-0, 11 KOs) to demonstrate versus Vargas that at 24 he has developed into a more multifaceted fighter than he has shown.

“Callum has relied on the power of his right hand in past fights,” Roach said. “In this training camp, we have really focused on a two-fisted attack. Callum has become more comfortable and confident in using his left not just to set up his right, but as an additional weapon. He’s been devastating in sparring, and I can’t think of a better place to show this off than on the Canelo-Crawford card.”

Netflix will stream the Walsh-Vargas bout immediately before Alvarez (63-2-2, 39 KOs) faces Crawford (41-0, 31 KOs) for his Ring, IBF, WBA, WBC and WBO 168-pound crowns. The four-fight Netflix portion of the card is scheduled to begin at 6 p.m. PT (9 p.m. ET; 2 a.m. BST).

Roach appreciates the expansive platform on which Walsh will perform, thanks in large part to his relationship with Dana White. The UFC president and CEO is the front man for TKO Boxing, the promoter of record of the Alvarez-Crawford card, and he has consistently shown Walsh’s fights on UFC Fight Pass.

“An impressive performance on this huge platform,” Roach said, “will propel Callum into the mainstream for fans and media around the world. It’s a great opportunity.”