ESPN Boxing

After a two-week search for a new opponent, Paul Williams has one. He will meet junior middleweight titlist Sergio Martinez in a nontitle middleweight bout Dec. 5, Williams promoter Dan Goossen told ESPN.com Wednesday.

Williams and Martinez, both southpaws, will meet in the 12-round main event of HBO's "World Championship Boxing" in Atlantic City, N.J., at the Adrian Phillips Ballroom, the smaller, upstairs arena inside Boardwalk Hall.

Williams was originally scheduled to challenge middleweight champion Kelly Pavlik for the title in the main arena. However, the fight was canceled Oct. 21 when Pavlik withdrew for the second time because of persistent problems with his left hand stemming from a staph infection and two subsequent surgeries. Pavlik and Williams were originally scheduled to fight Oct. 3, but that date was pushed to Dec. 5 before being canceled.

In Martinez, Williams will face one of the top junior middleweights in the world.

"It's a tough fight against what many would consider an unknown champion, but Martinez can't be underestimated," Goossen said. "He's hungry and he's been looking for his opportunity to fight a name fighter. This is it. Martinez has everything to gain from this fight. [Williams trainer] George [Peterson] and Paul are cognizant of the fact that Martinez can go out there and cause problems.

"These are the types of fights that are the tough ones, a fight made off the cuff because of the circumstances we were faced with Pavlik pulling out on short notice. Normally, you'd rather have a much bigger window to prepare for a tricky left-hander like Martinez," he said.

Said Lou DiBella, the co-promoter of Martinez: "I think it's as competitive a fight as you can make for Williams right now. These are two guys that most people don't want to fight. Nobody is running to fight either guy. I think Sergio has a lot going for him in this fight. He's unusually fast and strong for a left boxer. He has pop and speed and he's not a little guy."

Heavyweight Cristobal Arreola (27-1, 24 KOs), who was stopped in the 10th round of a one-sided title challenge to Vitali Klitschko on Sept. 26, will return to face an opponent to be determined in the televised co-feature.

Although Martinez holds a title at junior middleweight, the bout will be over the 154-pound division limit, which both sides readily agreed to.

Williams had been training for months in anticipation of facing Pavlik in October and then in December so "Paul was training to be a middleweight, not a junior middleweight," Goossen said. "It would not be in his best interest to come down to 154 now on short notice. So I think it's reasonable to keep him in the division he was looking to fight in."

For Martinez, it's a free shot at a top fighter without risking his title, although Williams has a rematch clause should he lose.

"We didn't object to the weight because of simple reality," DiBella said. "We're not going to object because whatever happens, Sergio retains his belt and that is fine with us. The main thing is this is a good fight."

Williams (37-1, 27 KOs), 28, a former two-time welterweight titlist and former interim junior middleweight titlist, will be fighting at middleweight for the second consecutive bout. In April, he easily outpointed Winky Wright in a near-shutout decision.

Williams claimed an interim 154-pound title last November but has not defended it. Still, it was a surprise to Goossen that Williams had apparently been stripped of that title on Wednesday when promoters of Saturday night's Alfredo Angulo-Harry Joe Yorgey HBO fight announced that the WBO had approved it for the interim title.

"We did not receive any notification," Goossen said. "But this fight is not about which belts these guys have. It's about the best fighting the best. This is about the fighters."

Martinez, 34, a native of Argentina living in Spain, claimed an interim junior middleweight title when he stopped Alex Bunema in the eighth round in October 2008. He defended it once on a controversial majority draw against Kermit Cintron in February, a fight the overwhelming majority of observers believed Martinez (44-1-2, 24 KOs) clearly won. Martinez was elevated to a full titleholder in July after titlist Vernon Forrest was murdered.

Before Williams-Martinez was finalized, Goossen also looked at titleholder Sergei Dzindziruk and former welterweight titlist Joshua Clottey. Dzindziruk, however, is mired in a promotional dispute with Universum and Clottey turned down the fight because he didn't want to move up in weight.

"We also made the obligatory reach-out to Shane Mosley, but there wasn't any interest," Goossen said. "Even though Paul can make the weight, we're destined right now to wave goodbye to the welterweights. They just don't seem to have any interest in stepping into the ring with Paul."

The fight will mark the Atlantic City debut for Williams, an Atlanta native who trains in Washington, D.C. He's been fighting mainly on the West Coast, where Goossen's company is based, but Goossen hopes to use the fight with Martinez to establish Williams on the East Coast.

"We had some sites in Las Vegas and Los Angeles that we could have moved to [after Pavlik, the big draw in Atlantic City, fell out], but I felt it was important to establish a base for Paul on the East Coast," he said. "I believe Paul will be a big hit in Atlantic City. This is exactly what you try to accomplish with a fighter at the doorstep of becoming a star -- build up a following on both coasts."

Dan Rafael is ESPN.com's boxing writer.