Bryce Harper is already a good ballplayer, probably very good. If he never got better, he would have a fine career. But he is not great. Not yet.

History and observation suggest that he will be — probably within the next couple of seasons, not “someday.” But that leap is still a hypothetical and a huge challenge, unless you think .270 with 59 RBI and some mis-tracked flyballs constitute greatness — and no one knows the difference better than Harper.

On Monday, Harper became the first everyday player to win rookie of the year for his performance as a teenager. He deserves it. Right pick, even though his seven-point margin over 16-game winner Wade Miley of Arizona in the National League race was narrow.

Including his throwing arm, speed to run down balls and aggressive-bordering-on-nuts base running, Harper had perhaps the best all-around season ever by a teenager. But he’s also lucky he plays for Davey Johnson, who might be named NL manager of the year on Tuesday.

It would be hard to imagine a better match than the Washington Nationals’ confident, outspoken old manager, nearly 70 years old, and a brash extroverted young player, now 20, to face what will be fair, yet almost insane, expectations for Harper next season.

Johnson was also the manager of the only pitcher ever to win rookie of the year for his teenaged exploits: the Mets’ Dwight Gooden, who fanned 276 in 1984. The next year, with sky’s-the-limit demands on him, Gooden went 24-4 with a 1.53 ERA. With the New York media and fans demanding “more . . . more,” Doc produced it.

Can Harper? We’ll see. But be glad Davey’s next to him. Kryptonite to hot rookies is the sophomore jinx. The cure may be confidence squared. In Johnson, Harper has a unique mix of teacher, critic and booster.

Johnson has called Harper “maybe my favorite player ever” for his ferocious, uncompromising style. If any young, potentially great player ever needed such a staunch experienced backer, it’s probably Harper. Why?

Now that Harper has done dazzling teenage deeds, including score 98 runs despite playing just 139 games while amassing 57 extra-base hits, he will suddenly move to an entirely different scale of measurement. And it could be a shock to anyone’s system.

So many of those 20- to 22-year-olds became most valuable players — or batting champs or home run kings — within just two years of being rookies of the year that comparisons are not only going to be inevitable, they are also going to be appropriate. But they will be staggeringly difficult to match.

Mike Trout’s amazing season at age 20, for which he won the American League award Monday, just sets the comparison bar higher for Harper. Bryce and Trout are buddies, and Harper never shies from measuring himself.

Since the rookie award began in 1947, some of baseball’s greatest players have won the award at extremely young ages, from 20 to 22. But despite their youth, they were already close to their prime.

Players such as Johnny Bench, Albert Pujols, Frank Robinson, Orlando Cepeda, Cal Ripken and Eddie Murray were nearly fully formed stars when they won it. Pujols hit .329 with 130 RBI. Robinson had 38 homers. Derek Jeter hit .314 for a World Series winner and Evan Longoria hit six postseason homers to help the Rays to the Series. And this year, Trout hit .326 with 129 runs and 49 steals.

On the same MLB-TV show that announced Harper’s award, his 2013 season was already being compared to Trout’s numbers at 20, an MVP-worthy performance.

That’s not fair.

Harper may accept it. Privately, he may even relish it as motivation. As often happens with Harper, he sometimes seems to have a better grasp on his place in the baseball scheme than others.

“Icing on the cake,” he called the award. As for his 2012 goals, “I didn’t reach ’em,” he said, then added that, “I want to win a World Series. I want to put that ring on my finger and give that to the town and city of D.C. They deserve that.

“We didn’t reach that. Nothing else really matters to me.”

Some won’t believe that. Perhaps no one is that team-centric. But Harper has always listed Pete Rose and George Brett as primary heroes. He knows the game. He realizes whom he’s picking. Rose wanted to pass Ty Cobb in hits and Brett wanted to hit .400, not .390. But both were famous within their own clubs as the epitome of “us first,” not “me first” players.

Asked to look back on his whole season, an open-ended question he could have taken in any direction, including back toward himself, Harper said: “It was a lot of fun with a great group of guys. They made it the way I wanted it. Play hard. Play the right way.”

What about being sent back to AAA to start the season? Harper talked about what he learned at Syracuse from Jason Michaels.

Jason Michaels? Yes, 36-year-old veteran, over 1,000 games in the majors, somebody who could teach you something. After all, Harper learned from Jayson Werth how to take a secondary lead from third base when a left-handed pitcher (such as Cole Hamels) makes a routine pick off throw to a left-handed first baseman. If you know that detail, added to a detail, on top of another detail, you might get a good enough jump to steal home on a guy who put you on base by drilling you with a pitch.

Right now, that really is Harper’s core level: baseball, baseball, could I have some more baseball please, sir. Who knows when or if that gets old, but it certainly hasn’t yet; and it’s the mostly likely path to the kind of rapid, almost breathtaking improvement that other off-the-charts talents have made in their early 20s. If you aren’t rocketing up now, you may never.

You can hear in Harper’s voice that he doesn’t entirely expect to be believed, like he’s watched the “Bull Durham” cliches 500 times too many, yet his play, so far, always seem to back up his words.

“I love [the game] with everything I got,” he said. “I’m going to play every day like it’s my last.”

Oh, don’t put it that way. Everyone wants another two or three thousand days of Bryce Harper. Winning rookie of the year at 19 is the first solid chapter of a truly special career. Many more will be needed — and demanded. From everything Harper’s shown so far, they will probably be provided.

For previous columns by Thomas Boswell, visit