Junior dos Santos and Shane Carwin have a few things in common. Each has stepped into a mixed martial arts cage or ring 13 times. Each has walked out a winner after all but one of those bouts.

And then there are a couple of big similarities: Each has a pair of hamhock fists with the shattering impact of bowling balls.

When dos Santos and Carwin square off in the main event of UFC 131 Saturday night in Vancouver, B.C. (PPV at 9 p.m. ET, free prelims on the UFC's Facebook fan page at 5:50 and Spike at 8), fans of fisticuffs will be in for a treat.

A short and sweet treat, most likely.

Of these heavyweights' combined 26 fights, only one has gone the distance. All but three have ended in the first round. Five of Carwin's bouts and two of Dos Santos' didn't make it out of the first minute.

Bruce Buffer's "It's tiiiiiiiime!" might take more time than Saturday's fight. If John McCarthy is the ref, he might only be able to manage "Let's get it--" before someone has gotten it.

As Dos Santos said during a brief hype-it-up interview broadcast during last weekend's The Ultimate Fighter 13 finale on Spike, "Don't blink."

Then he smiled.

Then cable company and satellite provider phone banks began to ring as if Ron Popeil had just barkered a special deal on the Chop-O-Matic or Pocket Fisherman.

Actually, despite the hook of a Rock 'Em, Sock 'Em showdown, the PPV numbers for this card almost assuredly will fall short of what Dana White and Co. envisioned when they scheduled UFC 131. Originally, it was to be topped by a No. 1 contenders bout between the coaches on this season's TUF reality show, Dos Santos and former UFC champion Brock Lesnar, the organization's undisputed PPV kingpin.

How big a draw is Lesnar? Brock was in the main event of the UFC's two most profitable pay events, facing Frank Mir at UFC 100 in July 2009 (1.6 million PPV buys) and a then-unbeaten Carwin at UFC 116 last July (1.16 million). Add in Lesnar's bouts with Cain Velasquez at UFC 121 last October (1.05 million) and with Randy Couture at UFC 91 in November 2008 (1.01 million) and you've got four of the top six PPVs in UFC history.

But with a season's worth of TUF hype already finished taping in Las Vegas and in mid-run on Spike, Lesnar had to pull out of UFC 131 a month ago because of a relapse of the diverticulitis that first derailed his fight career -- and nearly his life, or at least life as he knows it -- two years ago. Lesnar underwent surgery and is on the shelf until (he hopes) 2012.

Enter Shane Carwin, last seen pummeling Brock for a round last summer before gassing himself and getting choked out in the second. And instead of an Octagon chess match -- can the smaller Dos Santos avoid being smothered by the beefy Brock? Can Lesnar withstand Junior's fast fists, a speedbag attack even more dizzying than what overwhelmed him in his last two fights? -- the fans will get their Fourth of July fireworks display a little early this year.

78: Power punches he landed on Roy Nelson in his last bout, a unanimous decision win (the only decision on the resume of either dos Santos or Carwin) last August at UFC 117.

7: Consecutive victories. Two of them (over Fabricio Werdum in October 2008 and Gabriel Gonzaga in March 2010) earned Knockout of the Night bonuses.

10: Number of his 12 fights that have ended by KO, TKO or an opponent's submission because of either an injury sustained from being punched or exhaustion from withstanding a Dos Santos beatdown.

104: Average number of seconds in his fights. Ten of Carwin's 12 bouts have ended within two minutes, five in less than a minute. Prior to his last two outings -- a KO of Mir at 3:48 of the first and a submission to a Lesnar arm triangle at 2:19 of the second -- Shane's average fight time was barely over a minute, at 67 seconds.

163: Seconds faster he was than Dos Santos at knocking out Gabriel Gonzaga. Junior finished Gonzaga at 3:52 of the first round in March 2010, while Shane was pulled off by the ref just 1:09 into his fight with Gabe in March 2009.

100: Punches he threw in the first round of his last bout, landing 57 and nearly putting away Lesnar ... but punching himself out himself in the process.

Since numbers don't tell the whole story ...

This shapes up to be a grappling duel worthy of the Abu Dhabi Combat Club Submission Wrestling World Championship, with two guys rolling around on the mat seeking openings for submissions or dominant positions.

Yeah, right.

Actually, both of these guys do have ground-fighting pedigrees. Carwin was the 1999 Division II national champion while wrestling for Western State College of Colorado. Dos Santos owns a brown belt in Brazilian jiu-jitsu, training under Antonio Rodrigo Nogueira and Anderson Silva.

But taking the fight to the ground is not likely at the top of the list in these guys' respective strategies. Plan A is the right fist, Plan B is the left, and Plan C is to throw an even harder shot with the right. Grappling is maybe Plan D -- that's "D" for desperation. A guy who gets rocked with a punch can use his grappling skills to bide time while his head clears.

In the most feasible scenario, when these fighters go to the mat, one is likely to be writhing and disoriented, the other pouncing in order to viciously finish.

It's been a long time since we've seen a fight for the UFC heavyweight championship. This bout will set one up, with the winner to face Cain Velasquez for the big-boy belt sometime in the fall.

What else do you need to know?

"I'm always looking for the knockout in my fights, and this fight will be no different. Shane Carwin can walk through some punches. He's a really tough guy. But I have a lot of belief in my hands and the power in my hands, and I think Shane may have never felt power like I have." --Dos Santos during a UFC 131 conference call with MMA media last week

"Lets face it: Both dos Santos and I got to where we're at by knocking people out on our feet. I think we're both explosive fighters, and I think the fans are going to have a real treat come UFC 131 when it gets to that main event, knowing both guys have knockout power in their hands." --Carwin during the same conference call

Working overtime: As fighter nicknames go, "The Engineer" doesn't exactly strike fear in anyone, like "The Ax Murderer," "The Dean of Mean" or "Twinkle Toes." Oh, wait, strike that last one. But "The Engineer" fits Carwin to a T-square because he's, um, an engineer. That's not his former career, from before he became an elite-level fighting machine. Shane still does the 9-to-5 thing for the North Weld County Water District in Lucerne, Colo., except when he's on leave for a fight. Imagine calling over to the water company, irate that your pipes are dry, and having Shane answer because the receptionist is at lunch. "Hey, I haven't been able to take a shower for two days!" you yell into the phone. "When is one of you idiots going to come over here and do something about it?"

He roams around, around, around: Since we're on nicknames, Dos Santos' is "Cigano," which means "gypsy" in Portuguese. From what I can gather from various online stories, Junior was given the name by friends after he left home at age 18 and spent a time traveling around his native Brazil.

Comings and goings: Carwin made his UFC debut May 24, 2008, with a 44-second KO of Christian Wellisch at UFC 84 in Las Vegas. That same night, down in Brazil, dos Santos fought for the final time outside the Dana White Athletic Club, stopping Geronimo dos Santos (no relation) in the first round at Demo Fight 3 in Salvador, Bahia. What else happened that day? Dick Martin of Rowan & Martin's Laugh-In saw the Fickle Finger of Fate for the last time in this life, and Bob Dylan and Tommy Chong celebrated a birthday, though presumably not together.

And on the undercard ...

When Kenny Florian makes his featherweight debut in Saturday night's co-feature, he'll be carrying a big question mark on his back. Will the longtime lightweight be weakened by having to cut an extra 10 pounds, or will a physique that has allowed him to compete all the way up at middleweight make him too much to handle? The answers to these questions might provide the UFC with fodder to set up Florian as a stout challenger for dominant and dynamic champion Jose Aldo. Or maybe not. Maybe Kenny will feel fine but still be overwhelmed by 16-1 Diego Nunes, Aldo's training partner, last seen beating former champion Mike Brown on New Year's Night.

Dave Herman bears the nickname "Pee-Wee," which brings all sorts of funny thoughts to mind, like, Does he fight while wearing a too-small glen plaid suit with red bow tie? But the guy is no joke. Herman is 20-2, with 14 KOs. He's making his UFC debut against another promotional first timer, Jon Olav Einemo, who was supposed to fight Carwin until Shane was moved to the main event. Aside from being surely the top MMA fighter in Norway, Einemo is a Brazilian jiu-jitsu black belt who shined on one of the sport's big stages, the ADCC Submission Wrestling tournament, winning the championship in 2003. And the word on the streets of Oslo is that he's the one who stole Pee-Wee's shiny red Schwinn bike.

Just so you don't feet cheated if the main event features not a second of grappling, the UFC is providing a bout whose most exciting action likely will be on the ground. Demian Maia, a fourth-degree black belt in Brazilian jiu-jitsu, multiple-time champion at Abu Dhabi and one of the top submission grapplers in MMA, faces 2001 NCAA Division I wrestling champion Mark Muñoz, a two-time All-American. The ref should just start these guys in the center of the cage, with Muñoz in Maia's half-guard.

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