Through Wednesday’s games, Bryce Harper is hitting .366 with an on-base percentage of .448 and a slugging percentage of .657. (Jonathan Newton/WASHINGTON POST)

There’s a lot the Washington Nationals don’t know yet about Bryce Harper, and a lot that Harper doesn’t know himself. Heck, until a few weeks ago, none of them knew Harper was basically Mr. Magoo in eye black. So General Manager Mike Rizzo’s pronouncement now, in mid-May, that Harper will not be seen at Nationals Park this season makes perfect sense. Frankly, the biggest surprise, to me, was that there was anyone out there still arguing that the Nats should bring up an 18-year-old kid for what is likely to be the mop-up (and at this rate, the makeup) games of September.

Practicality says the Nats don’t want to start Harper’s free agent clock any sooner than necessary. But there are many other reasons as well for keeping him down on the farm for the entire season.

The Nats need to turn him into a top-flight outfielder. They need to see how he handles pitching at any level above Class A. They need to see how he handles a slump, or adversity of any kind, for that matter. Because Harper hasn’t had a lot of setbacks in his baseball life. He’s nearly always been the best player on the field. Somewhere along the way, that will change. The Nats need to be sure Harper can handle that.

When Rizzo says, “He’s got to learn the nuances of the game of baseball,” he’s not trying to denigrate Harper and dent his confidence — which he has in abundance. Harper has the speed to get to balls in the outfield, and his numbers there aren’t bad — but he doesn’t always throw to the right base, and he sometimes throws home when he shouldn’t. And he’s not always sure what to do on the base paths.

But oh, the bat, the glorious bat. He’s hitting .366 with an on-base percentage of .448 and a slugging percentage of .657 (through Wednesday). Those are crazy-good numbers, especially when the Nationals are dead last in the league with a .223 team average. Harper’s numbers, impressive as they are, came at Class A Hagerstown of the South Atlantic League. He could put up good numbers — not those numbers, but good ones — against major league pitching right now. But that’s not enough for a call-up.

It’s tempting to let Harper leap-frog the necessities because he’s done so, successfully, for much of his career. He skipped two years of high school by getting his GED, then played only one season of college ball, and still was the No. 1 pick in the 2010 draft.

But it’s not as easy — or as wise — to skip steps in the minors, which are designed with precisely the mandate of getting players such as Harper ready for the big leagues by putting hitters against progressively better pitchers, and and vice versa.

Stephen Strasburg, who had pitched three years of Division I college ball at San Diego State, only tested out of Hagerstown and high-Class A Potomac, starting instead at Class AA Harrisburg. And Strasburg is four years older — with four more years of experience — than Harper.

So Harper is better off where he is for now, learning to handle those “nuances” — such as hitting breaking balls from good minor league left-handers — rather than trying to learn those same lessons against great major league lefties. Harper’s time will come, and it will be something to see. But it hasn’t come yet.