As quickly as he was removed from the UFC 137 card, Nick Diaz is back on. The outspoken former Strikeforce Welterweight Champion will now battle “The Prodigy” B.J. Penn at the October 29th event in Las Vegas, Nevada. UFC President Dana White confirmed the news earlier this evening.

Yesterday, White announced that Diaz had been removed from the UFC 137 main event against Georges “Rush” St. Pierre for failing to show up to a pair of mandatory press conferences. White said that Diaz could not be trusted, but he nevertheless added Diaz back to the card’s co-main event today.

Diaz (25-7-0, 1 ND) has not lost in almost four years and made three defences of his Strikeforce title before rejoining the UFC ranks this summer. He most recently scored a come-from-behind knockout victory over Paul “Semtex” Daley in a back-and-forth April bout that ended late in round one. Though highly-regarded for his ground skills, Diaz has knocked out 13 opponents to date and most felt that his best chance of stopping St. Pierre was with strikes. Against Penn, Diaz will face a fellow jiu-jitsu practitioner with an iron chin.

Penn (16-7-2) formerly held both the UFC Lightweight and Welterweight Championships. He won six of seven fights from 2007 until 2009, with the lone defeat coming in a title rematch with St. Pierre. Despite the loss at 170 to St. Pierre, Penn retained his 155-pound title, but he lost it to current champion Frankie “The Answer” Edgar in a razor-thin April 2010 bout. After a second loss to Edgar, Penn returned to the welterweight division, where he knocked out rival Matt Hughes and fought to a contentious Majority Draw with Jon Fitch in February.

While Diaz held a perceived advantage in striking power over St. Pierre, Penn arguably represents an even tougher challenge for the Stockton, California native. Penn has never been submitted in his career and is renowned for having one of the best chins in the sport. Diaz and Penn will face off in the new co-main event on the card.

UFC 137 takes place on October 29th at the Mandalay Bay Events Center in Las Vegas, Nevada. The event will be headlined by a UFC Welterweight Championship bout between Georges “Rush” St. Pierre and “The Natural Born Killer” Carlos Condit.

UFC 137 Fight Card (to date; subject to change):

– Georges “Rush” St. Pierre vs “The Natural Born Killer” Carlos Condit [UFC Welterweight title]
– “The Prodigy” B.J. Penn vs Nick Diaz
– Matt Mitrione vs Cheick Kongo
– Mirko “Cro Cop” Filipović vs Roy “Big Country” Nelson
– Hatsu Hioki vs George Roop

– Donald “Cowboy” Cerrone vs Dennis Siver
– Tyson Griffin vs Bart “Bartimus” Palaszewski
– “Crazy” Tim Credeur vs Brad Tavares
– Scott “Young Guns” Jorgensen vs “The Big Frog” Jeff Curran
– Brandon “The Truth” Vera vs Eliot “The Fire” Marshall
– Danny “Boy” Downes vs Ramsey Nijem

(Photo Credit: Sherdog.com)