The undercard for the Naoya Inoue vs. Ramon Cardenas fight, set for May 4 at T-Mobile Arena in Las Vegas, is starting to take shape.

Rohan Polanco will face Fabian Maidana in a ten-round welterweight fight, while Emiliano Vargas will face an opponent to be named in an eight-round junior welterweight fight. Both fights will be part of the ESPN+ portion of the card, and will precede the main card on ESPN, which will feature Inoue-Cardenas for the undisputed junior featherweight championship, plus WBO featherweight titleholder Rafael Espinoza defending against Edward Vazquez.

“Rohan and Emiliano are emerging superstars and welcome additions to this incredible card at T-Mobile Arena,” said Top Rank Chairman Bob Arum, who will co-promote the event in association with Ohashi Promotion, Teiken Promotions, and Sampson Boxing. “Before Inoue and Espinoza defend their titles, fight fans will have the opportunity to watch two future world champions in action.”

Polanco, 15-0 (10 KOs), a 2020 Olympian representing the Dominican Republic, is coming off a destructive second round knockout of Jean Carlos Torres in February. Maidana, 24-3 (18 KOs), of Buenos Aires, Argentina is the younger brother of former champion Marcos Maidana and has yet to be stopped in his pro career. The 32-year-old Maidana has won twice since losing last May to Mario Barrios by unanimous decision for the interim WBC welterweight belt.

“This fight is a major challenge for me, but it’s also a great platform to showcase my skills in front of a massive audience. This is a great step forward for my career and will give me a chance to earn new fans while proudly raising the Dominican flag,” said Polanco in a press release.

Vargas, 13-0 (11 KOs), also has a famous boxing relative as the son of former junior middleweight champion Fernando Vargas. The 20-year-old from Oxnard, California is riding high on a four-fight knockout streak, and is coming off a second round stoppage of Giovannie Gonzalez just this past weekend.

“To fight at T-Mobile Arena on Cinco De Mayo Weekend, alongside incredible champions like Naoya Inoue and Rafael Espinoza, is a great opportunity. I kicked off my 2025 campaign in style last week and will continue that momentum with another standout performance on May 4,” said Vargas.

Also set for the undercard, Mikito Nakano, 12-0 (11 KOs), of Tokyo, Japan will make his U.S. debut against Puerto Rico’s Pedro Marquez, 16-1 (10 KOs), in a ten-round featherweight fight. The southpaw power puncher is rated in the top ten by all four major sanctioning bodies. In another undercard bout, Raeese Aleem, 21-1 (12 KOs), will compete in a ten-round featherweight bout against an opponent to be named.