The smile, however, quickly disappeared when Fielder donned a batting helmet and stepped into the cage himself. The 6-foot, 250-pound, barrel-chested youngster presents quite an imposing image at the plate, employing a controlled, compact swing that can send the ball to any field with power.
Yet, as Fielder popped up one ball after another, only occasionally sending a shot into the gap at Herschel Greer Stadium, the frustration was mounting. This was only batting practice after all, but Fielder clearly wanted no part of what was happening. As he finished his first round in the cage, he slammed the bat in disgust and trotted to first base.
By the time Fielder finished rounding the bases, it was obvious there would be no more joking. He picked up his bat, stood behind the cage and watched his teammates take their swings, keeping an eye on them and the pitcher before stepping back into the cage himself. This time, Fielder got the desired results, hitting the ball with more authority, the way one would expect of a power-hitting prospect.
"I was pissed off," Fielder said about his first round in the batting cage. "But I'm usually like that, whether I do good or bad. It helps me stay focused. When you do well, you don't like to be too happy because you know you're not perfect. But I'm trying to be."
The Brewers don't need Fielder to be perfect. He's one of their top prospects, a breath away from the Major Leagues, and for now, they're perfectly happy with how he's progressing. Fielder is already one of the more feared hitters in the Pacific Coast League and is usually an attraction whenever the Nashville Sounds head to a visiting town.
While some of that has to do with his bloodlines -- his dad Cecil Fielder was smacking home runs for Detroit more than a decade ago -- most of it has to do with his own ability. Fielder hit 63 homers through his first two and a half Minor League seasons, while driving in 241 runs. Though his first seven weeks at Triple-A haven't produced the same kind of power numbers -- he had only three homers and 14 RBIs through 32 games -- no one is worried about Fielder.
After all, this is the kid who hit a ball out of Tiger Stadium as a 12-year-old while using a wood bat and put on a power-hitting exhibition at Spring Training during his junior year of high school for an impressed Tigers team.
"He's a special talent," Milwaukee's director of player development Reid Nichols said. "He's going to be a very good hitter in the big leagues at some point. There have to be adjustments, though. His first two games [this year], he hit home runs and thought this might be easier than it is. When the veteran Triple-A pitchers stay away from him, he gets a little frustrated.
"His on-base percentage is outstanding, though. Sometimes he'll go out of the game plan and swing at some outside pitches, but mostly he stays in the game plan and that's very hard to teach."
Though everyone expects the long ball from Fielder, his discipline at the plate is proving to be his greatest asset. Nichols mentioned his ability to "stay within the game plan"; a sentiment echoed by Nashville manager Dave Kremblas, who marveled at Fielder's ability to take a pitch.
Fielder had 21 walks, which was tied for the team lead, through the first part of the season. While some of that comes from opposing pitchers being cautious, most of it comes from the youngster himself. Southern League managers chose him as the player with the "Best Strike-Zone Discipline" last year as part of Baseball America's "Best Tools" survey.
"He doesn't chase bad pitches," said Kremblas, who managed Fielder last season in Huntsville. "He has the strike zone discipline of a Major Leaguer."
As a high-school athlete in Florida, Fielder said he had dreams of playing basketball, not baseball. But he realized his lack of height and his size wouldn't permit that. So, he concentrated on baseball, yet he never considered himself a home-run hitter. Perhaps that's why he has become so adept at recognizing pitches now because he wasn't swinging for the fences earlier.
"I wanted to hit line drives," he said. "When you're known as a home-run hitter, people pitch around you. If you're a line-drive hitter, just keep hitting them and sometimes they go. They're going to make you try and hit their pitch. That's good for me. I can see how it is and get used to what it's like being a big-league hitter. It gives me a chance to get in extra work."
Fielder turned 21 on Monday and though there are many pressures on him, he doesn't let it show. He's already a father, has had to grow up as the son of a famous ballplayer and now carries the hopes of an organization on his shoulders as well. He handles it all with aplomb.
"This has been a lot of fun so far," Fielder said of his journey. "I've made it all the way to Triple-A, which is the last stop before my real dream of playing in the Major Leagues. Baseball is fun, man. That's the easy part."
Kevin T. Czerwinski is a reporter for MLB.com. This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.