This spring, several of them have one pitch in common when they face Stewart -- the kind that sails out of the park, or at least off outfield walls. Through Friday, Stewart carried a .485 batting average (14-for-29) with team highs in home runs with five and RBIs with 12.
The power is befitting of his status as the top prospect in the Colorado organization and one of the top third base prospects in the game, along with Kansas City's Alex Gordon, the Los Angeles Dodgers' Andy LaRoche, Cleveland's Andy Marte and Washington's Ryan Zimmerman. Stewart, who turns 21 on April 5, is the youngest of the crew, with Gordon having turned 21 last month and Marte and Zimmerman set to celebrate their 23rd birthdays during the season.
Stewart is slated for Double-A Tulsa, but the Rockies expect to have their hands forced soon. Stewart, with 57 home runs in 300 Minor League games, could make his Major League debut before season's end. But what that means at third base -- where Garrett Atkins' ability to hit for average if not power has already forced Jeff Baker to try the outfield -- is to be determined. Atkins finished fourth in National League Rookie of the Year balloting last year.
"I guess I'm slated to start at Tulsa, and I'm looking forward to that a lot," Stewart said. "We're going to have a great team there. That's all I'm really looking forward to right now, just getting that season started with Tulsa, and if I'm doing well, you never know. All I can do is go out and play the game.
"I had a lot of confidence coming in [to Major League Spring Training]. I knew I didn't have anything to lose. I wanted to show them what I could do and play hard and have fun. It's still the same now, but my confidence has grown a little bit now that I'm playing well."
For now, the Rockies are simply happy that they have someone so prepared.
"I think we've talked about it all -- his humility, his work ethic," Rockies manager Clint Hurdle said. "He has a unique passion for the game. He leads by example. In the groups that he's been in, that's been talked about."
Stewart's Minor League stat sheet likely would be even more impressive if the beginning of his 2005 hadn't been marred by a Spring Training hamstring injury. Stewart hit .221 in his first 44 games, but batted .308 the rest of the way, with hits in 52 of his final 68 games. He managed 17 homers and 52 extra-base hits.
What's more important to Rockies standout first baseman Todd Helton is that Stewart has tools that will play in the big time.
"He's got power," Helton said. "You could tell the first day he had a lot of power, but he's very impressively driving the ball to center field and left-center field with power. He's the real deal. He's only going to get better.
"There are a lot of strong guys but they don't get it out of their swing. He gets every bit of strength into his bat speed and his power. That's good. He really stays through the ball and the bat stays in the zone a long time with power."
The first of Stewart's homers came off Diamondbacks lefty farmhand Doug Slaten, and he's also had one against D-Backs left-handed Minor Leaguer Mark Freed. But the rest have come against pitchers with Major League experience -- Oakland righty Chad Gaudin, Arizona righty Kevin Jarvis and Milwaukee lefty Jason Kershner.
"I keep track of these guys," Stewart said. "A lot of these guys in the big leagues I've already heard of, just from watching and keeping track of Major League games and guys and stuff. It's fun to come out and face these guys that I've read about."
Now folks will be tracking Stewart.