He was a rookie, playing shortstop as he had all his life. He was a vocal leader who wore his refusal to accept losing on his sleeve. Being a centerpiece of an unexpected World Series trip was a dream, but certainly not a fantasy. Finally, after the season, what others saw finally dawned on him.
"I did a lot of talking at some events," Tulowitzki said. "It might not come out the best all the time, but people came up to me afterwards and said, 'We can tell you really have a love for the game, and we really appreciate your talking. It came from the heart. It wasn't made up. You can tell.'
"That meant a lot to me. It made me realize that maybe I am a little mature for my age."
Tulowitzki didn't turn 23 until Oct. 10, the day before the National League Championship Series opened. By rewarding Tulowitzki with a six-year, $31 million contract, the Rockies have a good chance to see his age catch up to his maturity.
Tulowitzki's eye-popping rookie season was the stuff of the record books, from his unassisted triple play against the Braves on April 29 (13th in history), to his 99 RBIs (most all time for a rookie shortstop), to his 24 home runs (most ever by an NL rookie shortstop), and to his .987 fielding percentage (tops ever for a rookie). His clubhouse announcement in Phoenix that he had never lost and wasn't going to start now is club legend, especially since it marked the beginning of a Rockies turnaround.
But the best way to measure Tulowitzki's growth may be to watch him now in the Hi Corbett Field clubhouse and remember him a year ago at this time.
Keep in mind, nothing really has changed. Tulowitzki thought then that he would be a vocal leader. He acted as such on the field, directing traffic and hitting teammates with a cold stare and admonishments when throws went awry or were misdirected. That's who he'd always been.
The Rockies placed his locker in the central area of the room. In pro sports, unestablished rookies are expected to fade into the background. Merely being where he was, where any reporter or even any veteran wanting to give him a hard time could find him, served as a test to see if he could be a part of the team and not stand out.
In a sense, there was one common thread between the way Tulowitzki handled himself on the field and the way he navigated the clubhouse. He was smart about both.
"I haven't changed much as a guy," Tulowitzki said. "I've always had this energy and I like to make jokes. But last year I wasn't in position to do that. You're coming in, fighting for a job, the last thing you want to do is open up your mouth and have guys start to say things about you."
"Now I feel like I have a pretty good friendship with these guys. We all became pretty close. We give each other some stuff, but it makes it fun, but it makes the locker room a place you want to come every day."
This spring, Tulowitzki dresses in a corner with some of the club's most trusted veterans. And those vets speak of him as someone who has earned his acclaim.
"We'd have smacked him around if he'd come in here with anything other than a humble attitude," standout left fielder Matt Holliday said. "This group will not allow anybody to get too full of himself. He knows that we wouldn't allow him to be anything other than a hard-working young guy who plays winning baseball. I think that's what we pride ourselves on, that nobody's bigger than the team. 'Tulo' is one of my good friends and somebody I think very highly of."
An up-close look at the club as we approach Opening Day
Longtime veteran first baseman Todd Helton said, "He's a good dude. He's going to be around for a long, long time. His overall makeup is perfect to be very successful in this game for many years. And he's exciting to watch play, and I've got a front-row seat to it."
Missing from all the praise for Tulowitzki is the fear that the years and money will turn out to be a bad investment.
Ironically, Tulowitzki's biggest drawback last season might have provided reassuring information.
By season's end, Tulowitzki was as popular as any Rockies player. Boys pushed for autographs and their dads wore jerseys with his name and number. Women of all ages swooned. Come playoff time, his at-bats were greeted with rhythmic handclaps followed by shouts of "Tulo!"
But the cheering then faded into the postseason. He went 8-for-41 (.195) during the three postseason series. After the Red Sox completed the four-game sweep of the World Series, Tulowitzki stared at the celebration from the dugout. The anger and disappointment showed on his face well after the game, when he finally ambled to the shower.
A week later, Tulowitzki was back at work, driven by his postseason disappointment.
"I think he's like a lot of our guys," Rockies manager Clint Hurdle said. "They expect a lot out of themselves and are looking for ways to better themselves. They know better than anybody what they can and can't do and what they should have done.
"His progress obviously is on the fast-learning track. He's picked things up very well. He pushes himself extremely hard. It just shows he's forward-thinking."
Tulowitzki is mature enough not to look back at 2007 for anything other than to learn from it.
"You can't try to impress everybody because you've got a big contract," Tulowitzki said. "You've got to just worry about yourself and get better each and every day. I'm looking to build off my season last year, and with the team, continue success and make this a winning organization."
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.