The other day, Jason Heyward mentioned that the Atlanta Braves are “a young team.” That sounded funny, given that Heyward has been around long enough to have played for Bobby Cox and with Troy Glaus, both of whom exited after the 2010 season. If anyone on this young team qualifies as an elder statesman, it’s Heyward, who is …

Eleven weeks shy of his 25th birthday.

He was 20 when he hoisted the mammoth Opening Day home run off Carlos Zambrano, still 20 when he was named to the 2010 All-Star team. That Heyward hasn’t graced an All-Star roster since has led some among us — I concede that I’m occasionally guilty — to wonder if he wasn’t overhyped. But to see Heyward on his good nights, of which there have been many, and to grasp what he has come to mean to the Braves, which is a lot, is to put aside such doubts.

At his worst, Jason Heyward is an excellent big-league player. At his best, he’s among the very best. That he hasn’t been at his full-blown best since his giddy-to-everyone-except-Heyward rookie season — Heyward has never seemed giddy, not even on that famous Opening Day — doesn’t mean he won’t ascend to that exalted plateau on a more regular basis.

One of the reasons the Braves signed Freddie Freeman and Andrelton Simmons to long-term contract extensions this winter was that they have a good idea what those two exemplary players are apt to do over the next few seasons. That they re-upped Heyward only through 2015 didn’t mean they don’t value him; it meant they’re still trying to assess that value. They know he’s very good. They believe, as they’ve always believed, that he can be great.

Basic numbers — the back-of-the-baseball-card stuff — don’t begin to take Heyward’s full measure. He entered Wednesday night’s game against Milwaukee hitting .235 (and this after going 7-for-18 to add 20 percentage points) with three homers and 10 RBIs. That’s not the stuff of legends. But his WAR (wins above replacement) rating was 1.7 according to Baseball Reference, and that ranked him first among everyday Braves. Justin Upton’s WAR was 1.5; Simmons’ was 0.8, Freeman’s 0.6.

The point being: Even without hitting much, Heyward has been a big deal. His defensive WAR rating of 1.5 is the second-best in baseball, and he’s among the game’s smartest baserunners. There’s no reason to think such a gifted player can’t become a .280 hitter. The surprise is that he’s not one already.

He’s not impatient. Over his career, he has averaged 4.05 pitches seen per plate appearance, which is a healthy number. He strikes out too much, but this is 2014 and everybody strikes out too much. Last month Ben Reiter of SI.com quoted an unnamed scout as saying Heyward has a weakness against hard stuff on his hands, but that’s partly a function of physique. Heyward is 6-foot-5, 245 pounds. Freddie Patek he’s not.

But enough of that. The intent today isn’t to ascertain what Heyward isn’t (or isn’t yet) but to underscore what he is, and that’s the most important Atlanta Brave. He’s a big enough talent that he’s never just one of 25 guys. He’s the one guy who can change the dynamics for the other 24. It happened last season when manager Fredi Gonzalez made him the leadoff hitter, and it will happen again. When Heyward gets going, this team goes.

“No question,” Gonzalez said Wednesday. “He brings energy. When he gets on the basepaths, we’re a different team. He is the engine.”

Then this: “Even when he’s not hitting, he still brings energy. He prepares himself every day; he’s the same guy every day.”

He has been since 2010, but with Chipper Jones and Brian McCann gone, Heyward is the one outsize presence in this clubhouse. There’s a gravitas about him, a dignity that few 24-year-olds — heck, few 64-year-olds — ever attain. He’s still a young man, but he’s a pro’s pro.

“There’s never been anything bad about him,” Gonzalez said. “I never worry about him. The way he conducts himself, on and off the field … I’m never worried about him.”

Because Heyward has never acted young and because his rookie season was so stellar (a WAR rating of 6.4, fourth-best in the National League), we’ve tended to treat him as a nearly finished product. Owing to injuries and changing assignments — he has batted everywhere in the order but cleanup and ninth; last season ended with him leading off and playing center field — he hasn’t quite become what we envisioned. But that doesn’t mean he won’t get there, and it doesn’t mean he’s not essential. He can and he is.