When a promised main event falls apart, ninety-percent of the time we are left with a replacement match-up that leaves us sighing and wistful, longing for what could have been.  Not so at UFC 131!  Former heavyweight champ Brock Lesnar was going to face off against Brazilian bruiser Junior dos Santos for top contender status, but a few short weeks ago Lesnar bowed out due to illness (a recurrence of his diverticulitis).  His replacement: Shane “I will punch you to death or die trying” Carwin.  It’s not hard to describe why this pairing of devastating knucklemen is infinitely more compelling.  First, with Lesnar taking on dos Santos, we would’ve likely watched one big man attempt to lie on top of another with mixed success.  Second, if Lesnar had won, we would’ve likely watched him lose to champ Cain Velasquez in a fashion similar to before.  Now, however, we’ll be treated to something explosive and deadly, and regardless of whether it is dos Santos who wins or Carwin, whoever faces Velasquez next will be someone who may actually beat him.  Like I said, ninety-percent of the time a replacement main event sucks.  Hooray for UFC 131 being part of the other ten percent!  Here’s MMA Convert’s preview.

Junior dos Santos vs. Shane Carwin – Dos Santos may have a brown belt in jiu-jitsu, but his specialty is hitting people so hard that their pets die.  Carwin may have been a collegiate wrestler, but he’s so good at KO’ing people, the Navajo have dubbed him “He Whose Opponents Always Require a Post-fight Head CT Scan”.  The only knock against the American is his cardio – a weakness Lesnar exploited when he and Carwin fought.  Can dos Santos survive the early thunder and take his opponent into deeper waters?  Or will Carwin smash the amiable Brazilian and earn himself another title shot?  I have this one at 50/50, but regardless of the outcome, do not run off to the kitchen to refill your frosty mug of beer without first pressing “pause” on the DVR.  This one will be ending abruptly.

Kenny Florian vs. Diego Nunes – Remember in “The Sound of Music” when the nuns were all singing “How do you solve a problem like Maria?”  Well, the UFC has been singing that same song about Florian ever since it became clear that there are too many in the lightweight division he can’t beat.  Thankfully, “Ken-Flo” is competing at UFC 131 at featherweight, so problem solved, right?  Um, maybe.  We have to see how he does against the tough Brazilian grinding machine Diego Nunes.  Since coming into the WEC/UFC fold, Nunes has apparently forgotten how to finish fights, and instead prefers to drag things out to the bitter end.  If the cut down to 145 was rough, that may not bode well for the TUF 1 alum.  We shall see.  If it ends early, it’s because Florian has stunned Nunes with his Muay Thai and submitted him on the ground; if it ends late, Florian has been mushed into the cage for close to fifteen minutes.

Demian Maia vs. Mark Munoz – Maia is to jiu-jitsu what sharks are to biting surfers.  Unfortunately, Maia is to striking what sharks are to running marathons.  In other words, if the explosive wrestler and capable striker Munoz manages to dodge his opponent’s submission game, it could be a very short night, with Maia finding a comfortable spot on the Octagon floor to take a nap. 

Dave Herman vs. Jon Olav Einemo – The funny thing about this match-up is that if you’re a fan attuned to the non-UFC MMA world, you know Herman and Einemo as two dudes long overdue for their debuts on the “Big Show”.  In Herman, you have a well-rounded hard-hitter with experience for days, and in Einemo you have an absolute grappling beast (he won the Abu Dhabi Submission Wrestling World Championship back in 2003).  This pairing is very similar to Maia vs. Munoz, except Einemo can probably take a few knees and punches before he does his thing.  Look for him to force Herman to tap.

Donald Cerrone vs. Vagner Rocha – Rocha is a jiu-jitsu black belt making his UFC debut.  Cerrone is capable of winning on the feet and on the ground, was a top contender in the WEC, and, as evidence by his handling of Paul Kelly, he’s transitioned into UFC life nicely.  Cerrone is going to murder Rocha.  That is all.