A showdown between junior flyweight champ Ivan Calderon and hard-punching beltholder Giovani Segura, arguably the best matchup that can be made in the 108-pound division, is close to being finalized, according to Segura's manager.

THE RING’s No. 1-rated junior flyweight will challenge the magazine’s unbeaten champ on August 28 in Puerto Rico, Ricky Mota told RingTV.com on Tuesday.

“We’ve signed the contract, we’ve agreed to everything,” said Mota, Segura's manager, “and from what I’ve heard from Fernando Beltran (of Zanfer Promotions) and the Riveras (Peter and Ivan of PR Best Promotions, the promoters of the bout), Calderon is on board.”

In an email to RingTV.com, Ivan Rivera confirmed that the fight is close to being done.

“We are working on (finalizing the deal),” Rivera told RingTV.com. “It will be the best fight for the little guys for the past years. We are just waiting for Segura's contract before we make an announcement.”

Calderon-Segura will headline a PR Best-produced pay-per-view card in association with Top Rank and Zanfer, according to Mota. The show will take place in Guaynabo, Puerto Rico, the hometown of Calderon (34-0-1, 6 knockouts).

Calderon is scheduled to fight 108-pound “interim” beltholder Johnriel Casimero on the August 28 date, but Mota says the 20-year-old Filipino will now face Ramon Garcia Hirales in Mexico on July 24.

Segura (24-1-1, 20 KOs), a Southern California-based southpaw from Guerrero, Mexico, is scheduled to defend his belt against Manuel Vargas on August 7 on a Fox Sports en Espanol-televised bout from Lagos de Moreno, Mexico. However, that bout will be canceled, according to Mota, who says a press conference for Calderon-Segura is scheduled to take place in Los Angeles sometime next week.

“This is something we’ve wanted for a long time,” Mota said. “Calderon is the golden boy of the lower weight classes. Giovani wants to fight him to prove that he’s the best at 108 pounds. He was thinking of going up to flyweight (112 pounds) to fight for a title there because he didn’t think he would ever get the chance to challenge Calderon, so he’s pumped up that he’s finally getting the shot. He doesn’t mind fighting Calderon in his hometown. He says his hands will be the judges.”

The fight won’t cause major ripples in the sport but hardcore fans — especially those of Puerto Rican and Mexican descent — want to see if Segura can indeed impose his youth, power and relentless pressure on the quick, slick-moving southpaw.

The 35-year-old counter-puncher, who defended a 105-pound belt 11 times before winning THE RING's junior flyweight title in 2007, is lauded as one of the best pure boxers in the sport.