After all, he looks very much like the professional wrestlers he so admires. His entire wardrobe, in fact, consists of black T-shirts that say things like, "I'm not very smart, but I can lift heavy things."
And at first glance, you have no reason to think the shirt is lying.
"When you first meet him, he doesn't say very much," says his wife, Amy. "You start to think that maybe there's not much upstairs."
Well, obviously. Hafner's got to be the prototypical dumb jock, right? He probably didn't get an A in anything but Phys Ed.
"I loved math in school," he says proudly.
As in ... decimals? Not dumbbells?
"Did you know he was a Mathlete?" Amy asks. "He's really good at math. I bought some pens the other day, and I was trying to figure out how much they were per pen. I told him the total price, and he was like, 'It's $2.36 a piece. Aren't you impressed?'
"I don't own a calculator, because I just ask Travis to do it for me."
OK, so the big guy can do math. Big deal.
He's still got that gruff exterior. And he was born in North Dakota -- God's country. He must be the outdoorsy type, right?
"I'm a terrible hunter," Hafner says. "My brother and I would go hunting every year, but I can't hit anything. There could be a deer 10 feet away from me, and I'll find a way to miss it. Or I'll have the scope too close to my face and my nose will start bleeding."
Uh, all right. So Pronk can't hunt.
But he was raised on a farm. His father, Terry, grew wheat, barley, corn and flax. Terry taught his son the value of hard work. Surely, Pronk must love to use his hands for something other than swinging a baseball bat, right?
"He's not very handy," Amy says. "I'm the one who fixes the toilet or hammers things into the wall. You would think, growing up on the farm, he would know all that stuff. But his dad would be like, 'Get me a wrench,' and he'd bring him a screwdriver. He never really learned."
Well, he probably doesn't do handiwork because he's too busy sculpting his muscular physique.
And he no doubt must cover his body with some macho tattoos. Tribal designs. Skulls and crossbones. Heck, he probably has the word "Pronk" scrawled across his back in Japanese, right?
"I've kind of always wanted to get tattoos," he says. "But I think when I'm done playing baseball, I don't know if I'd really want the look."
Ah, he's just being careful. He doesn't want to get in trouble with his wife. She's probably the one who won't let him get a tattoo, right?
"He's definitely afraid of needles," Amy says. "He once had to get an ingrown toenail removed, and my dad is a podiatrist. My dad had to give him a shot of Novocain. Travis was pouring with sweat.
"Honest to God, he almost fainted. He got out of the chair and ... you know how they put paper on the chair? The paper was like wet toilet paper."
Well, by now it doesn't take a Mathlete to realize the 30-year-old Hafner doesn't have a personality that matches his gargantuan profile.
Pronk might attend WWE matches or blast Rammstein music in his Escalade, but he's just as likely to mix in a chess match or a simple game of fetch with Rudi, his 20-pound Australian terrier.
"I don't like too much excitement," Hafner says in a monotone delivery that is reminiscent of comedian Steven Wright. "I like to keep things nice and relaxed."
His wife concurs.
"He's so laid-back," she says. "Nothing's a big deal to him. He feels like you can work out anything."
That temperament served Hafner well in an '07 season in which he struggled to live up to expectations at the plate. While Pronk drove in 100 runs for the fourth straight season, his .267 average, 24 home runs, .385 on-base percentage and .451 slugging percentage were all marked declines from the year before.
As '08 dawns, the Indians are banking on Hafner returning to his old form. That's partly what inspired the Tribe to return virtually the same team that fell to the Red Sox in seven games in the American League Championship Series last year.
Hafner is the first to admit his '07, on a personal level, was not up to par. Off the field, he was dealing with the distraction of contract negotiations and some family health concerns. On the field, Pronk just wasn't quite Pronk.
"It was a tough year," he says. "But the team was winning, and that's always going to be my main focus. As long as we're winning, I'm happy. For the most part, I've put last year behind me and am just looking toward this year."
Spoken like a man who likes to keep things simple.
The fact that Hafner doesn't expound much on his plate performance should come as no surprise.
"He's kind of shy," Amy says. "But he told me one time that he never wants to be the guy that people say, 'Gosh, he talks too much. He's so annoying.' You'll never get that with Travis."
Nor will you get him to change his trademark wardrobe. The Indians took notice last year and released a Bobblehead that depicted Hafner wearing blue jeans and a black T-shirt, rather than his uniform.
Over the winter, Amy actually got Pronk to wear a new, white T-shirt.
She considered it progress.
"He has this pair of camouflage pants," Amy says. "Two years ago, his goal was to wear the same camouflage pants to the park every day. I finally washed them, and he didn't get to wear them to the park one day. He was pouting."
Pronk pouts? What is this guy, a wimp?
Well, no, not at all. Hafner might have his quirks, but he's still a typical guy in many respects.
His greatest passion away from baseball revolves around his fantasy football teams -- TPO (Technical Pronkout) and Pronktically Unbeatable. He's won the title in the Tribe's clubhouse league the last two years, and he's not afraid to brag about it.
"One more win, and it's officially a dynasty," he says. "My team would go down with the greatest fantasy football teams of all time."
And while Hafner won't stop talking about his teams, his teammate, Casey Blake, won't stop chirping about Hafner's little dog.
"My daughters take that dog for a walk," Blake says, "and they're four and six. What's that tell you?"
All right, so maybe Rudi isn't the most fearsome of dogs. But Pronk still takes pride in him.
"He loves playing fetch, and he's always running around growling," Hafner says. "He's got quite the personality on him. He's a lot of fun having around."
This, you see, is the Pronk you don't get to know when you rely on that misguided first impression. And Amy, who has gotten to know this supersized slugger better than anyone else, smiles when she thinks about her husband playing with Rudi.
"He's going to be a good dad," she says. "He loves that dog, and he's so patient with him. It's really cute ... I mean, not cute ... really tough. He told me I'm not allowed to give his tough-guy image away."