Obviously he needed a different approach, given his pitching career -- much like his fastball -- had been going nowhere fast with the White Sox Rookie League team.
So Haeger, whose older brother was the baseball coach at Madonna, abandoned his mid-80 mph fastball and began toying with a knuckleball. Now seven years later, he's in camp with the Mariners after pitching parts of the past five seasons in the Major Leagues with the White Sox, Padres and Dodgers.
"It was pretty much the only way I could get people out back then," Haeger said. "I'm not naïve. I know 84-85 [mph] is not going to get it done for a 6-foot-1 right-hander. I figured, hey, I've got to try something."
There's something tantalizing about watching a knuckleballer, whether you're a fan, coach or opposing hitter. The idea that a soft floater can challenge the game's best hitters when thrown properly seems hard to fathom, but then you watch catchers struggling to pull in Haeger's pitches during bullpen sessions and eyebrows raise.
"It's tough," said Mariners catcher Miguel Olivo, whose only prior experience with a knuckleballer came in the Dominican Winter League in '05. "I've caught him two bullpens already and only dropped four balls. So far it's good. But to be honest with you, that thing is nasty. I can't wait to see him in a game and see what's going on."
Haeger, 27, has had far more success at the Triple-A level than the big leagues to date, though he notes it takes years for knuckleballers to master their craft, as evidenced by the lengthy careers of Hoyt Wilhelm, Charlie Hough, Phil and Joe Niekro and current knucklers Tim Wakefield and R.A. Dickey.
Last year Haeger made the Dodgers' rotation out of camp, struck out 12 Marlins in his first start and then lasted just six starts and nine games in Los Angeles, going 0-4 with an 8.40 ERA.
But he continues to intrigue teams with his potential and the Mariners offered a Minor League contract and will look at him as either a starting candidate or long reliever.
Haeger's ball moves so much that he doesn't play catch with other pitchers while warming up, teaming instead with bullpen catcher Jason Phillips so as not to hurt anybody.
He throws his primary knuckleball in the 72-75 mph range, along with a slower version that has even more movement at 64-65 mph. And, yeah, he'll toss that 83-84 mph fastball occasionally just to keep hitters honest.
Like most knuckleballers, Haeger holds the ball with the tips of two fingers instead of wrapping them around with full grip. He originally tried a three-fingertip grip, but changed after watching Wakefield in slow-motion on TV.
Now he's worked extensively with Hough and talked with Wakefield to pick their brains.
"At first, it was great one day and the next it was like I'd never thrown it before," said the Michigan native. "It was just trial and error until finally I got relatively comfortable in trying to throw it in a hula hoop of the strike zone. That's really what I'm trying to do. I'm aiming at the catcher's mask and just letting the ball do what it does. It took a while."
The fact there aren't more big league hopefuls attempting to master the art of the knuckleball is a testament to its difficulty.
"It's a pitch that can save your career and give you some longevity," Haeger said. "But it's a tough pitch to master. It really is. I'm far from it. You look at a guy like Wakefield, he's been doing it 17-18 years. Even R.A., he's 35 and last year was a great season for him. He's had six, seven years where he's up and down and then last year it kind of snapped in."
Mariners pitching coach Carl Willis says he's never had a knuckleballer on one of his regular-season staffs and is learning about Haeger and his art as well. He and manager Eric Wedge said they'll be patient with Haeger, knowing the knuckleball is a "feel pitch" that takes time and repetition. They'll also have to account for the fact that Arizona's desert air changes the way most breaking balls react.
"You have to be aware that the action and movement they're going to get on the ball here in Arizona is a little different than it's going to be in other places," Willis said. "But what we need to look for is for him to throw it over the plate, because that's where things start. I don't think you can necessarily judge how much it's going to dance all the time here in this climate."
Haeger acknowledged that the knuckler works best in more humid weather, but he's spent all 10 of his Spring Trainings in Arizona and says he's the one who mostly controls how well the ball moves. What he can't control is how he's viewed.
It's easy to see the potential of a young prospect throwing 97 mph fastballs. Counting on one whose 65 mph pitches dance unpredictably requires a larger leap of faith.
"It's a hard thing [for teams to] trust because you just don't see it very often," Haeger said. "That's the biggest thing, really. Once we get more comfortable here and I get more comfortable with Carl and Eric and these guys, I think it'll be a little easier for them. It all depends on how the games go. Bullpens are good, but it's tough for them to get a grasp until we get some live action."
But Haeger's ball is moving very well early in camp. On Wednesday, he worked with a Minor League catcher who was continually handcuffed by his throws. Haeger said it's actually a good sign when his catcher struggles since it means he's getting good action.
It remains to be seen where he fits into the Mariners plans, but he said his craft continues to improve and he feels he'll get a chance with Seattle.
"I like what Eric is doing so far," he said. "There are a lot of good young arms here and this organization is definitely taking a turn in the right way getting all these guys in here. Eric really wants to take this thing to the next level in Seattle. It's good. I'm excited."