Who knew?

Some baseball folks assert they foresaw this version of Didi Gregorius, or at least something close to it. Others admit they didn’t.

“There were people that thought he could hit for power. There were people that thought he could hit right-handed and left-handed pitching,” said Tim Naehring, the Yankees’ vice president of baseball operations. “They thought he was a guy who thought he could be an All-Star, yes. There are reports that would back that.”

“No, I didn’t. I can’t sit here and lie,” Yankees hitting coach Marcus Thames said. “But I knew he was a heck of an athlete who didn’t really have a chance in Arizona.”

You’d be missing the point of Didimania, however, if you tried to keep score on who called this and who didn’t. Because the whole point of this story is that Gregorius knew.

He knew what he didn’t know, thanks to his humility and open-mindedness. He knew how to apply what he learned, thanks to his intelligence.

And, thanks to his confidence, he knew that he would have the final say on his fate.

“Like I’ve said, I’m not going to let people put labels on me,” Gregorius reiterated in an interview this past week. “Because it’s a lot of things people can say, but at the end of the day, who’s the one working?”

In the wake of a 2017 season that set career highs across the board and concluded with a memorable October, Gregorius (who hasn’t been an All-Star yet, for the record) is off to the sort of start that puts one in the Most Valuable Player conversation. He earned American League Player of the Month honors for April after leading the major leagues with 10 homers and 30 RBIs and ranking second with a 1.116 OPS.

If it’ll be a challenge for Gregorius to match the overall career of Derek Jeter, the franchise icon he succeeded at shortstop in The Bronx, he just might meet Jeter’s peak.

“He’s doing everything right,” Astros manager A.J. Hinch said. “Maybe he’s been left out of some of that shortstop love which has been sprinkled around different parts of the American League. There are a lot of good ones, most notably the one we have at short [Carlos Correa]. I think Didi’s an exceptional player, whether he’s coming into [his] own or whether he’s always had this talent and he’s put it together for an incredible first five or six weeks.”

“He’s kind of picking up right where he left off in the playoffs last year,” Naehring said. “He controlled the zone in the playoffs. We’ve seen that here in the early stages of ’18.”

Controlling the strike zone, theoretically a perpetual goal of any team, has graduated into a platinum-level Yankees buzzword this year. Gregorius should earn a bonus as the initiative’s face. If you want to understand how Gregorius has looked so good so early, you start with his increased ability to control that zone.

“One thing we talked about in spring training, our whole club, was controlling the strike zone,” Thames said. “Showing guys where they’re doing damage at, with heat maps, and having the discipline to stay in that zone.

“My main thing, I want to eliminate weak outs. To eliminate weak outs, you’ve got to stay in your zone, where you drive the ball. And if you do that, you’re going to get really good results. And so far, so good for Didi. He’s had the discipline, and he’s really worked hard at it.”

“We were just talking about trying to get on base more and see how they pitch me,” Gregorius said. “Try not to chase. That’s what I’m trying to do. It’s not easy. It’s still in progress.”

If it’s still in progress, then Lordy, the Yankees’ opponents had best brace themselves for what’s to come. Gregorius’ chase rate — the number of pitches outside the strike zone at which he swung — has dropped to 31.6 percent, his best in the four years that MLB.com has been tracking such data, as per its Baseball Savant website. Last year, Gregorius’ chase rate was 38.2.

In accordance with his passing on junk, Gregorius’ hard-hit ball percentage has skyrocketed from 20.8 to 37.6 percent, though his average exit velocity has climbed modestly from 84.4 mph to 85.6. That seeming contradiction can be explained by the fact Gregorius’ weak-hit ball percentage also has increased, from 4.7 percent to 7.9 percent, a data point that Thames could not explain.

Furthermore, Gregorius’ pull percentage has leaped from last year’s 35.9 percent to 47.5 percent.

“Because they’re throwing me inside more,” Gregorius said. “They say I’m pulling. When they shift, where are they going to throw me most of the time?”

Actually, MLB.com’s measures show a modest increase of pitches to the inner third of Gregorius’ zone or inside, from 20.8 percent last year to 21.8 percent. So Gregorius deserves credit for doing more with what he is seeing.

“If they throw me inside, I’ll pull it,” he said. “If they throw me away, I’ll try to go the other way. Like [Tuesday], when I hit the ball to left-center [for a ninth-inning double], that was a fastball on the middle-outer third [from Ken Giles]. I just try to go based on how they pitch me, basically.”

“You go watch the video,” Thames said, backing his player. “The balls are in there. I don’t want him taking that ball and trying to fist that ball to left field. If it’s in that area, drive the baseball, and good things happen. He’s not trying to lift the ball. … He just lets the athleticism take over.”

Put together all of these elements, and you get a player whose on-base percentage has shot up from .318 in 2017 to .403 in 2018.

Gregorius combines his athleticism with what appears to be an equally natural curiosity.

“I think Didi’s a guy who is really easy to talk to,” said Astros bench coach Joe Espada, who scouted Gregorius as a Yankees trade target in 2014, then became the Yankees’ infield coach in 2015, Gregorius’ first year in pinstripes. “I think he understood that for you to be great, you’re going to have to be open-minded. And especially in New York, you’re going to have to have all of the people around you to have success.”

“You always want to learn. My way is never being satisfied,” Gregorius said. “There’s always room for improvement. So that’s how it’s always been, and I’m always trying to get better. That’s all I’m trying to do.”

He truly does not impress himself easily. When The Post asked Gregorius if a correlation existed between his ability to speak four languages (Dutch, English, Papiamentu and Spanish) and his knack for absorbing knowledge on the field, he shook his head and said, “It’s a completely different ability, because four languages are taught. It’s mandatory to learn four languages in Curacao.” He wanted no extra credit for the four-languages thing.

Hence he proved a perfect match for the Yankees, who have tried to match their financial might with intellectual heft. Their acquisition of Gregorius from Arizona in a three-way trade in December 2014 — the Diamondbacks had received him from the Reds in a December 2012 three-way trade, and the Reds signed him for $50,000 out of Curacao in 2007 — marked an initial step in their turn toward a younger, more athletic roster, a philosophical change they deemed necessary to keep up with the industry.

“All the credit in the world, for me, goes to Brian Cashman for making the deal and trusting his different departments,” Naehring said. “And then, once he was acquired, the credit should go to Didi and the coaching staff. Because there are guys that worked tremendously hard with Didi to put him in a position to succeed like he’s doing now for us.”

With his free agency coming after next year, the Yankees have yet to approach Gregorius about a long-term extension, he said, and he told The Post in March he’d be open to such an agreement. The lure of retaining Gregorius and passing on free-agent-to-be Manny Machado, especially if Machado insists on staying at shortstop, grows with each Didi homer to right field.

“He’s really been fun to watch,” Naehring said. “I’m very happy he’s in pinstripes.”

That, we all know.