Two very uniquely different heavyweights will be making their promotional debuts on the main card of UFC 131 this Saturday night (June 11, 2011) as Dave Herman takes on Jon Olav Einemo.

Dave Herman was and is still one of the sport's top heavyweight prospects. He was able to destroy opponents despite preparing for fights on his own and partying with friends before Japan gave him a heavy dose of reality in early 2009.

He's trying to prove the hype is real in his Octagon debut.

Jon Olav Einemo is a world-renowned submission expert but will be entering the Octagon with one of the largest cases of ring rust in history after having last competed in November of 2006. At 35 years old, he's looking to make one last impact in the world of MMA.

Has Herman stepped his game up since switching camps to Team Quest with Dan Henderson? Does Einemo still have it in him after nearly five years away from the sport? Which Dave Herman will show up....the brash ball of clay or the refined killing machine?

Check out our complete fight preview after the jump to find out:

Dave Herman

Record: 20-2 overall, 0-0 in the UFC

Key Wins: Ron Waterman (EliteXC: Return of the King), Yoshiro Nakao (WVR: Soul of Fight), Don Frye (Shark Fights 6)

Key Losses: Choi Mu Bae (Sengoku no Ran 2009)

How he got here: Dave Herman made a name for himself by becoming one of MMA's top heavyweight prospects despite not taking the sport seriously or training hard for much of the first three years he competed.

"Pee Wee" burst onto the scene in EliteXC, scoring three straight knockouts of MMA veterans Mario Rinaldi, Kerry Schall and Ron Waterman all inside the first six minutes.

Herman took his "no-train" attitude to Japan where he would lose to Choi Mu Bae after gassing early in the second round. The midwestern fighter would then take his game back stateside where he would go under contract with Bellator and become embroiled in a power struggle for his contract after failing to receive a second fight from the promotion for over a year.

He finally settled things with the upstart promotion this past September with one final fight and signed with the UFC after defeating the infamous "Herring-kisser," Yoshiro Nakao, at Sengoku's "Soul of Fight" event on New Year's Eve.

He was originally slated to face Rob Broughton but after injuries to UFC 131 fighters, he was paired up with Joey Beltran before the dust settled with Jon Olav Einemo.

How he gets it done: Herman is a complete enigma. The talented young fighter relied purely on his freak athleticism and natural ability for much of his career.

He used horrible technique but his unusual style, raw power and diverse array of attacks won him the day much of the time.

Hopefully, Herman's recent switch to Dan Henderson's Team Quest in California will do him a tremendous service. He has excellent wrestling and will likely want to use that grappling skill defensively to keep the fight standing and look to land his heavy hands.

Herman has been known to hang his hands all the way down and leave his chin exposed when he strikes. Hopefully he's been improving his defense while training with "Hendo" and Sokoudjou in the last few months.

If Herman scores a stoppage, it won't be with submissions. He'll either try to blast Einemo standing or with ground and pound if he can take the Norwegian jiu-jitsu king down and blast through his guard.

Jon Olav Einemo

Record: 6-1 overall, 0-0 in the UFC

Key Wins: James Thompson (2H2H: Pride & Honor)

Key Losses: Fabricio Werdum (Pride 31)

How he got here: Jon Olav Einemo is an esteemed Brazilian jiu-jitsu specialist. At the turn of the millennium, he used his offensive grappling skills to earn three first round stoppage victories in the European MMA circuit.

After taking a short break to compete in the world level of jiu-jitsu tournaments, Einemo would return in 2003 and score two more submission victories in less than three minutes combined.

Einemo would leave again for three years, winning his weight class at the Abu Dhabi Combat Club in 2003 and he is also the only man to ever defeat Roger Gracie in the ADCC.

Einemo would again return to MMA in 2006 but would lose to Fabricio Werdum at Pride 31 via unanimous decision. After defeating James Thompson with a first round arm bar, he would again step away from MMA for nearly five years.

He announced his return to the sport and the UFC gobbled him up. He was originally scheduled to face Shane Carwin but when Brock Lesnar's diverticulitis returned, he was paired up with fellow promotional newcomer Dave Herman.

How he gets it done: There's no doubt that Einemo will enter the UFC as one of the most technically sound Brazilian jiu-jitsu experts. He'll likely want to use his offensive grappling to take this fight to the ground where he can work ground and pound (Herman has been TKO'd once before) or hunt for submissions.

Einemo's best chances of winning the fight are on the ground, but, then again, he's been training at Golden Glory recently alongside world class strikers like Alistair Overeem.

There's a possibility that he's been refining his striking in his years away from the sport and he enters the Octagon as a completely well-rounded mixed martial artist.

Regardless, striking is Herman's biggest strength so look for Einemo to clinch or shoot on "Pee Wee" early and often. If he can put the American on his back, his odds of winning this fight increase significantly.

Fight "X-Factor:" There are so many "X-Factors" for this fight, it's not even funny but we'll limit it to three.

Number one: Is Einemo for real? Sure he did great things in sport jiu-jitsu but he lost the only fight against a credible opponent in his career. His biggest win was against James Thompson for crying out loud.

Number two: Did Herman finally take a fight seriously? He's a freak athlete with heavy hands but that will only take a fighter so far. Hopefully, training with Dan Henderson at Team Quest has helped mold him into an absolute wrecking ball but old habits die hard.

Number three: What does Einemo have left? The Norwegian BJJ master last fought MMA when he was 30 years old. That's an incredibly long time. Maybe he's been able to become stronger since then but in five years, there's no way he's faster with better reflexes. As fighters age, they have to use their experience to make up for their declining physical gifts. There will be a nine year age difference going into this bout and that may very well be the largest "X-Factor" of them all.

Bottom line: When it's all said and done, this match is a total mystery. There are so many questions about each fighter that it's practically impossible to predict how the fight will play out. It could be an entertaining stand-up war, especially if Einemo's been improving his striking with Golden Glory or it could be a hug-fest in the clinch while Einemo desperately attempts to work takedowns but is stuffed. Hell, it could be a one-sided beatdown from either fighter on the ground.

The aura of uncertainty with this fight is what makes it so intriguing.

Who will come out on top at UFC 131? Let us know in the comments section below!