Mike Chiappetta • E-mail

After 15 months away, Randy Couture finally returns to the octagon to find it a different place from the one he thought he was leaving for good. Though still officially considered the UFC heavyweight champion, there is an interim champion (Antonio Rodrigo Nogueira) waiting in the wings. New heavyweight prospects have arrived, threatening to shake the division’s balance. And the man he will be facing on Saturday hadn’t even made his UFC debut at the time of Couture’s departure.

Time moves quickly in the world of MMA, and Brock Lesnar’s mix of freakish athleticism, affinity for promotional soundbytes and proven drawing ability moved him quickly to the front of the line.

Time moves quickly in the world of MMA, with an exception for Couture, who seems to ward off Father Time at every turn, but now faces a stern challenge from Lesnar, who cuts weight to make the heavyweight limit of 265 pounds, and will likely outweigh Couture by around 50 pounds at fight time.

Despite his inexperience, Lesnar has been installed as the favorite. Couture, meanwhile, has made a career of beating the odds, setting the stage for either another legendary chapter or the coronation of a new king.

So how will UFC 91 go down? Let’s take a look at Couture-Lesnar, as well as some of the other key bouts.

Randy Couture vs. Brock Lesnar

Couture’s record: 16-8
Couture’s strengths: Clinchwork, experience
Couture’s quotable: “I have to find a way to make [my experience] an advantage. I’m a pretty fair athlete myself. I move fairly well, but Brock’s a big, strong, explosive guy, so I certainly don’t want to just stand in front of him.”

Lesnar’s record: 2-1
Lesnar’s strengths: Power, speed, wrestling
Lesnar’s quotable: “Speed plus mass equal destruction. Every day, I’m trying to sharpen my hands and how I execute my punches. I suspect Randy, I could be wrong, but I think Randy wants to stay away from my hands. He might be threatened by them, but who knows? I’m sure he’s ready for anything. All I can do is sharpen my skills and game plan.”

Keys to the fight: The 45-year-old Couture has a wealth of experience that can only be gained in big-match settings. He has to find a way to put Lesnar in situations he’s unfamiliar with and exploit them. He can try to wear Lesnar down with dirty boxing from the clinch, but it’s going to be hard to keep Lesnar against the cage. He needs to be a moving target and make Lesnar chase him. If he takes Lesnar down he must try to finish, because the opportunity might only present itself once. Remember, Couture went through the same on-the-job transformation that Lesnar is now undergoing, so he likely has a good idea of where Lesnar is in his progression as full-fledged mixed martial artist.

Lesnar is an explosive wrestler, but his standup has also improved, and he has a big reach advantage on Couture. With a wrestling pedigree to rival that of Couture coupled with a huge weight advantage, Lesnar will likely score a few takedowns, where he can use his size to wear down the champ. Remember, they may both be heavyweights, but the 50-pound size differential is akin to a 155-pound lightweight taking on a 205-pound light-heavyweight. The size challenge is a daunting obstacle.

What’s at stake: The UFC heavyweight championship. Couture thinks he’ll be able to exploit the holes in Lesnar’s game. Lesnar plans to forcibly take the torch from the man who brought mixed martial arts into the modern era.

Likely outcome: Lesnar by TKO. It is nearly impossible to bet against Couture, who has thrived as an underdog, but Lesnar’s wrestling skill along with his 50-pound weight advantage might be too much to overcome, even for the legendary “Natural.”

Kenny Florian vs. Joe Stevenson

Florian’s record: 10-3
Florian’s strengths: Muay thai, Jiu-jitsu

Stevenson’s record: 29-8
Stevenson’s strengths: Wrestling, strength

Keys to the fight: Since losing in a bid for the lightweight title back in Oct. 2006, Florian seems to improve every time out, and has won five straight fights. Florian game plans well and executes, utilizing his underrated striking and an improved wrestling game. It will be interesting to see which man is the better wrestler, because their ground games are both strong, meaning whichever man scores takedowns might be able to squeeze out rounds. On their feet, Florian has the advantage.

What’s at stake: Florian was thought to be the lightweight No. 1 contender after beating Huerta. He’s trying to keep his place in line while champion B.J. Penn takes a break from the division and moves up a weight class to take on Georges St. Pierre in January.

Likely outcome: Florian by decision. This has all the makings of an exciting fight with two fighters who have reputations as finishers.

Gabriel Gonzaga vs. Josh Hendricks
Hendricks hasn’t lost since February 2005 while Gonzaga’s lost two of his last three, but Hendricks is making his UFC debut while Gonzaga’s been in the cage with beasts like Mirko Cro Cop and Randy Couture. Still, Hendricks was a two-time All-American in wrestling, and he spent some time training with Couture for this fight. Couture had a perfect game plan for Gonzaga, and those tips from the master could very well play dividends.

Nate Quarry vs. Demian Maia
Very simply, one man (Quarry) wants to keep the fight standing, the other (Maia) wants to take it to the ground. That game within a game will help decide the winner. Whoever succeeds dictating the location of the fight will likely win the fight itself.

Tamdan McCrory vs. Dustin Hazelett
With Amir Sadollah suffering a leg injury that forced him off the event, the broadcast will promote a matchup of two of the UFC's youngest fighters, a pair of 22-year-old welterweights. McCrory is 9-1 and coming off a win over Luke Cummo. He has an awkward style but shows a well-rounded game. Hazelett (11-4) has exhibited a dynamic ground attack, coming off a beautiful armbar submission win over Josh Burkman. This could be fight of the night material.