A matchup between light heavyweight contenders Rashad Evans and Thiago Silva will headline UFC 108 on January 2 in Las Vegas, the UFC today announced.

Heavyweight contenders Antonio Rodrigo Nogueira and Cain Velasquez were to meet in the card’s main event, which was announced just last week, but Nogueira was forced to withdraw from the bout due to a severe staph infection in his left elbow.

UFC heavyweight champion Brock Lesnar will be sidelined indefinitely as he continues to suffer from illnesses that recently forced him to postpone his scheduled title defense against Shane Carwin, while Antonio Rodrigo Nogueira has been forced to withdraw from his matchup with fellow heavyweight contender Cain Velasquez which was to headline UFC 108.

Former lightweight champion Sean Sherk will return to the Octagon against Rafaello Oliveira at UFC 108 on January 2 in Las Vegas.

UFC 108 is headlined by a matchup between heavyweight contenders Antonio Rodrigo Nogueira and Cain Velasquez and also includes Rashad Evans vs. Thiago Silva, Junior dos Santos vs. Gabriel Gonzaga, and Carlos Condit vs. Paul Daley.

A recently-reported matchup between heavyweight contenders Antonio Rodrigo Nogueira and Cain Velasquez will headline UFC 108 on January 2 in Las Vegas, the UFC announced on Tuesday, with the winner guaranteed a title shot against the winner of the upcoming fight between champion Brock Lesnar and challenger Shane Carwin.

The UFC also confirmed that Rashad Evans vs. Thiago Silva will co-headline the pay-per-view event.

Heavyweight challenger Shane Carwin confirmed on his official website today that UFC champion Brock Lesnar will be unable to defend his title at UFC 108 on January 2 in Las Vegas.

“My manager Jason Genet just told me that UFC 108 is not happening,” wrote Carwin. “Brock has Mono and what the UFC has told me is that I have earned the title shoot but I have to wait for the title holder.”

UFC heavyweight champion Brock Lesnar will be unable to fight Shane Carwin in the main event of UFC 108 on January 2, according to Heavy.com, likely leaving the traditional blockbuster event without a championship headliner.

Illness prevented Lesnar from fighting at UFC 106 later this month and the fight was targeted for UFC 108, but with Lesnar still sidelined the bout will again be delayed, likely to UFC 109 on February 6.

Heavyweight contenders Cain Velasquez and Antonio Rodrigo Nogueira will likely meet in a featured matchup at UFC 108 on January 2 in Las Vegas, according to Tatame, which cites a report from Nogueira’s manager Ed Soares.

Velasquez is coming off a second-round knockout of Ben Rothwell at last month’s UFC 104, while Nogueira earned an impressive decision over Randy Couture in August.

Tickets for UFC 108, the UFC’s traditional year-end blockbuster event which takes place on January 2 in Las Vegas, go on sale next week.

With injuries sidelining title-holders Lyoto Machida, Anderson Silva, and Georges St-Pierre, BJ Penn headlining UFC 107 in December, and heavyweight champ Brock Lesnar potentially unavailable due to an extended illness, UFC 108, generally one of the most-stacked cards of the year, could be left without a championship headliner

UFC heavyweight champion Brock Lesnar, who last week withdrew from his scheduled title defense against Shane Carwin at UFC 106 due to an extended illness, remains sick and unable to train, according to an update from Yahoo Sports’ Kevin Iole.

If Lesnar is unable to resume training soon, the Lesnar-Carwin matchup could be pushed back until February and UFC 108 could be left without a championship main event.

Injuries to middleweight champion Anderson Silva and welterweight title-holder Georges St-Pierre could alter the UFC’s plans for early-2010, as both fighters may be sidelined longer than expected.

Silva’s recovery from recent elbow surgery could delay his title defense against Vitor Belfort rumored for UFC 108 in January, while St-Pierre may be unable to return until March.

UFC light heavyweight champ Lyoto Machida will soon undergo surgery that will postpone his immediate rematch with Mauricio “Shogun” Rua, according to Yahoo! Sports: “UFC officials have confirmed that Lyoto Machida will need surgery on one of his hands, thus delaying the planned middleweight championship rematch with Mauricio “Shogun” Rua”.

Welterweights Martin Kampmann and Rory Markham have reportedly agreed to square off at UFC 108 on January 2 in Las Vegas. Following his win over former WEC champ Carlos Condit, Kampmann was knocked out by Paul Daley in September, while Markham had his UFC record evened at 1-1 with a loss to Dan Hardy in February.

Welterweights Mike Pyle and Jake Ellenberger will square off on the UFC 108 preliminary card on January 2 in Las Vegas. Pyle earned his first UFC win over Chris Wilson in September, while Ellenberger dropped a hard-fought decision to Carlos Condit last month.

Middleweights Mark Munoz and Ryan Jensen have signed to meet at UFC 108 on January 2 in Las Vegas, according to MMAjunkie. Munoz (6-1) is coming off a win over Nick Catone in August in his 185-pound debut, while Jensen (14-5) notched his first UFC victory in September with a first-round submission of Steve Steinbeiss.

A lightweight matchup between Tyson Griffin and Jim Miller is in the works for UFC 108 on January 2 in Las Vegas. Griffin has won six of his last seven fights, including recent wins over Rafael dos Anjos and Hermes Franca, while Miller has gone 4-1 in the UFC with wins over the likes of Matt Wiman and Mac Danzig.