Mikey Garcia to fight Rafael Guzman

Featherweight contender Miguel Angel "Mikey" Garcia got a new opponent on Wednesday for his fight on Saturday night at the Staples Center in Los Angeles.

Garcia will face Rafael Guzman, who stepped in on four days' notice when original opponent Miguel Beltran Jr. was diagnosed with a fractured left hand and not medically cleared to fight, promoter Top Rank announced.

The scheduled 10-round bout will open the HBO telecast (10 p.m. ET/PT) headlined by middleweight Julio Cesar Chavez Jr. (42-0-1, 30 KOs), the son of Mexican legend Julio Cesar Chavez Sr., going for a world title against Germany's Sebastian Zbik (30-0, 10 KOs).

The injury to Beltran (24-1, 17 KOs), 21, of Mexico, took Top Rank by surprise.

"It turns out he hurt it last week and the doctor obviously wouldn't pass him after his physical," Top Rank's Carl Moretti told ESPN.com. "His hand was all bruised and battered. He couldn't really even close his fist that well."

Beltran was due to earn $75,000.

Top Rank quickly turned to Mexico's Guzman, 25, who has won 10 of his last 11 fights and is riding a three-fight knockout streak. However, in the one loss during the stretch -- five fights ago in March 2010 -- Guzman was knocked out in the first round by obscure Carlos Cardenas.

Guzman (28-2, 20 KOs) had been training for a fight on a June 11 Top Rank card, so he is in fighting shape and near the 127-pound contract weight, Moretti said.

"We pulled him off that show and, thankfully, HBO approved him," Moretti said. "He might be an even better opponent than Beltran. I guess we'll see. But once Beltran was out with the injury, we were putting Mikey in with Guzman, whether HBO was going to televise it or not. But they looked at his record and knew that he was in shape because he was scheduled to fight next week, so they kept Mikey's fight on the broadcast."

Garcia (25-0, 21 KOs), 23, of Oxnard, Calif., is one of the hottest featherweight contenders in the world. He will be making his second straight HBO appearance after stopping undefeated Matt Remillard in the 10th round on March 26 in Atlantic City, N.J.

Garcia was a mandatory challenger for a vacant 126-pound world title, but when HBO declined to buy the vacant title bout against Australia's Billy Dib, Garcia opted to forgo the title shot because the big HBO stage was more important to him.

Dan Rafael is the boxing writer for ESPN.com. Follow him on Twitter @danrafaelespn.