Mitrione grows while away from the cage

Off the mark: A green Matt Mitrione wasn't quite ready for the challenge Cheick Kongo presented. Mark J. Rebilas for ESPN.com

From the outside looking in, it’s difficult to imagine why heavyweight Matt Mitrione would approach UFC officials and ask to fight hard-hitting Roy Nelson.

Mitrione (5-1) has not fought in more than a year and he has undergone three surgeries during that span. Making matters more peculiar, Mitrione was on the short end of a unanimous decision when he last stepped in the Octagon (Cheick Kongo handed Mitrione his first professional loss on Oct. 29, 2011).

But Mitrione brushed all of these things aside when he got word that former interim heavyweight champion Shane Carwin had suffered a knee injury that forced him out of "The Ultimate Fighter" Season 16 Finale against Nelson on Dec. 15.

Mitrione’s request seems more peculiar when you factor in that he already had a Dec. 29 bout slated with Phil DeFries at UFC 159.

After a long layoff and surgeries to repair several injuries -- sports hernia, bone chips in an elbow and another that he still prefers not to disclose -- Mitrione couldn’t be more excited and ready to face Nelson on Saturday night.

“I’m champing at the bit,” the 34-year-old Mitrione told ESPN.com. “I’ve been out for a while and have had three surgeries in the past year.

“I’m ready. My body has healed up; I’m no spring chicken. Let’s get to dancing.”

A source of Mitrione’s excitement is the quality of sparring he received in training camp. Every day he’d have to go hard against former UFC light heavyweight champions Rashad Evans and Vitor Belfort at the Blackzilians gym in Boca Raton, Fla. And when those two were finished taking their pound of flesh, Mitrione would attempt to hold off former Strikeforce heavyweight titleholder Alistair Overeem.

Rarely did Mitrione get the better of his more-seasoned sparring partners. And he isn’t shy to say that those guys spent an overwhelming majority of the sparring sessions roughing him up.

“The amount of work that I’ve put in and the amount of ass-beatings that I’ve taken in camp have made me better,” Mitrione said. “I’m confident in my abilities and I’m confident in my mental fortitude to weather a storm.

“I’ve been weathering storms in camp since I got down here.”

But don’t confuse Mitrione’s admission of being roughed up in camp as a sign that he served as the resident punching bag. Every time a punch landed in his midsection, or he was taken to the ground or a kick connected with his lead leg, Mitrione learned from his mistakes. By the end of training camp, he was the victim of very few punches, kicks or takedowns.

He was also dishing out his share of punishment.

Mitrione is extremely confident he will look nothing like the guy who fought Kongo last year. And while he believes the fight should have been scored in his favor, Mitrione has a better understanding of what he could have done to sway the judges.

“I came in there to fight but Kongo didn’t really want to engage,” Mitrione said. “And I was too green to know how to force that fight. In my opinion, I should have won the first two rounds via control and aggression, but I didn’t get it and lost by decision. But one thing is for sure, Cheick didn’t beat me. Even if I’d won that fight, after having three surgeries I’d still be in the same boat I’m in right now.”

For Mitrione, facing Nelson is a great way to learn just where he fits in the UFC heavyweight landscape. Beating Nelson (17-7) could earn him consideration for a place among the division’s top 10.

Physical improvement is not the lone source of Mitrione’s positive prefight attitude. The heavy-handed heavyweight is stress-free these days. The yearlong layoff has allowed Mitrione, the father of three, to spend much-needed quality time with his children.

“I’m sure that everybody who is a professional competitor who travels a lot and has children knows exactly where I’m coming from,” Mitrione said. “I’m sure they can imagine it.

“There’s a lot of stress involved. There’s a level of guilt that you have if you’re a concerned parent when you’re not around your children.

“My 2-year-old daughter, Gia, was calling the phone daddy. That’s a lot to deal with. I was off for so long that I got to spend time with my kids again. I got back into the fold and it put my mind back in a good place.”