Vargas in after Guerrero fails eye exam

Nonito Donaire, one of the top pound-for-pound fighters in the world, has a new opponent after Gerson Guerrero failed his pre-fight eye exam on Wednesday.

Donaire (22-1, 14 KOs) was scheduled to defend his interim junior bantamweight belt against Guerrero in the main event of Top Rank's "Latin Fury 13/Pinoy Power 3" pay-per-view card on Saturday night at the Las Vegas Hilton.

Guerrero (34-8, 26 KOs), of Mexico, had a detached retina, Top Rank matchmaker Brad "Abdul" Goodman told ESPN.com. He was quickly replaced by another Mexican fighter: Manuel Vargas (26-4-1, 11 KOs), a former interim strawweight titlist who has also fought as a flyweight.

In his last bout in September, Vargas dropped a split decision to strawweight titlist Donnie Nietes of the Philippines.

Now Vargas will fight at junior bantamweight and challenge for Donaire's belt.

The two other names on Goodman's short list were Hugo Ruiz and former junior bantamweight titlist Jose "Carita" Lopez of Puerto Rico, but he was nowhere close to the 115-pound weight limit.

"I guess [Guerrero] has some sort of eye problem, but I am just ready for this fight," Donaire told ESPN.com moments after being told of the issue with Guerrero. "I've always been prepared to fight anybody. I can adapt to any changes. I am ready for anything. Whoever they put in, I'm ready if Guerrero can't make it. So be it."

Donaire said, if necessary, he was willing to make Saturday's fight in the 118-pound bantamweight division.

"As long as I get to fight, I am happy," Donaire said.

Cameron Dunkin, Donaire's manager who consulted with Goodman about a new opponent, signed off on Vargas.

Before the opponent was set, Dunkin said, "Nonito used to tell all the time that before I managed him, he never knew who he was fighting and he would take fights on short notice. He would say, 'I am ready for anybody. I'll work it out. Just let me know who it is and I'll be ready to go.' We'll get somebody and fight because Nonito is a fighter. A lot of guys would be blaming and complaining, but he's not like that. He's got a big smile on his face and says he's just ready to go."

Donaire, a former flyweight titlist from the Philippines but based in California, claimed his interim belt by outpointing Rafael Concepcion in August.

Donaire is hoping to use Saturday's fight as a springboard to a bigger fight against either unified division champion Vic Darchinyan, whom Donaire knocked out in a flyweight title fight, or titlist Jorge Arce.

Dan Rafael is ESPN.com's boxing writer.