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.

Nick Catone and Steve Steinbeiss will square off in a middleweight matchup at UFC Fight Night 20 on January 11 in Fairfax, Virginia, with their immediate UFC futures likely on the line.

Both fighters have lost two-straight coming into the bout, with Catone (7-2) losing to Tim Credeur and Mark Munoz following a debut win over Derek Downey, while Steibeiss (4-3) dropped his lone WEC fight to Carmelo Marrero before falling to Ryan Jensen in his first UFC fight.

UFC lightweight Corey Hill and middleweight Patrick Cote, both sidelined since 2008 with injuries, will return to the Octagon in 2010. Hill expects to return from his gruesome leg break in early-2010, possibly in January, while Cote says he’ll be back in action around April.

Welterweights Jon Fitch and Mike Pierce, both left without opponents due to a recent rash of injuries, have agreed to square off at UFC 107 on December 19 in Memphis, Tennessee. Fitch is coming off back-to-back wins over Akihiro Gono and Paulo Thiago, while Pierce has won six-straight, including an upset over Brock Larson in his UFC debut in September.

A previously-reported matchup between Houston Alexander and Kimbo Slice has reportedly been agreed upon by Alexander for The Ultimate Fighter 10 Finale on December 5 in Las Vegas and will apparently be contested at a 215-pound catchweight, according to NWITimes.com.

Lightweight Josh Neer has been released by the UFC after suffering a unanimous decision loss to Gleison Tibau last Saturday at UFC 104, his second-straight loss and third in his last four fights.

Heavyweight Pat Barry, who earned “Fight of the Night” and “Knockout of the Night” honors for his second-round knockout of Antoni Hardonk at UFC 104, will be sidelined at least two months to recover from surgery needed to repair a broken thumb suffered in the win. Barry has his sights set on fighting Stefan Struve when he returns to action.

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”.

Kurt Pellegrino has withdrawn from his lightweight matchup with Frankie Edgar scheduled for The Ultimate Fighter 10 Finale on December 5.

According to Fanhouse, Matt Veach, who had been set to fight Mark Bocek on the event’s preliminary card, is the leading candidate to replace Pellegrino, who is suffering from three herniated discs in his back and will be sidelined at least three weeks, with

A knee injury has forced Thiago Alves to withdraw from his rematch with fellow welterweight contender Jon Fitch at UFC 107 on December 12, according to Fanhouse. Reports indicate Alves should be able to return early next year and the rematch is likely to be postponed to UFC 108 in January or UFC 109 in February.

A long-rumored fight between Kimbo Slice and Houston Alexander may be in the works for The Ultimate Fighter 10 Finale on December 5 in Las Vegas, with MMAjunkie reporting Thursday that Alexander will soon apply to fight in Nevada and could square off with the Slice at the Spike TV-televised event.

TUF 8 runner-up Phillipe Nover will return to action against fellow lightweight Rob Emerson at UFC 109 on February 6 in Las Vegas. Nover, fighting for the first time since suffering a seizure in September, has dropped two-straight, while Emerson’s UFC record has been evened at 2-2 with back-to-back losses.

Team Rashad aimed to remain undefeated on episode seven of The Ultimate Fighter 10, as Matt Mitrione and Scott Junk squared off in the latest opening round matchup. Next week on TUF 10, Mike Wessel and Marcus Jones meet in the final first round bout and the quarterfinal matchups are determined.

Welterweights Josh Koscheck and Anthony Johnson have agreed to square off in the co-main event of UFC 106 on November 21 in Las Vegas, according to Sherdog.

Koscheck revealed on Twitter Tuesday that he’d be co-headlining the pay-per-view event, and while initial speculation focused on Matt Hughes, the knockout artist Johnson was ultimately tapped for the short-notice addition to the event.