VIERA, Fla. — For Juan Lagares, it’s as easy as painting by numbers.

The Mets center fielder is making the kind of plays this spring that earned him a Gold Glove award last season, but his bat might be overshadowing his defense for a change.

“He is definitely opening some eyes,” hitting coach Kevin Long said Thursday.

Lagares not only is making contact — as evidenced by his .383 batting average in 15 games — but producing loud hits. The latest two came Wednesday, when he delivered a two-run homer against the Yankees’ Dellin Betances in Tampa, and Thursday, he smacked another off Nationals reliever Jerry Blevins in the Mets’ 8-3 win.

What gives? For starters, Lagares has been among the star pupils of the visualization drills implemented by Long and his assistant Pat Roessler.

In a variation of an old drill in which colored tennis balls were fired from a pitching machine, the Mets are using painted baseballs in the batting cage. The baseballs each have a number written in a certain color, and hitters have to identify both variables on the pitched ball.

“The colored balls get him to home in on the baseball and then you really home in on where it’s coming in the strike zone,” Long said. “Juan is starting to see spin better on breaking balls. He’s starting to lay off sliders that are down and away off the plate, and it’s just helped him with his recognition.”

Lagares had a .281/.321/.382 slash line last season with four homers and 47 RBIs in 416 at-bats. The Mets see room for improvement on those numbers, especially if Lagares continues with his improved pitch selection. The 26-year-old considers the colored-ball drills beneficial to his plate discipline.

“I just do the same thing and I’m working hard every day and try to do what I do in practice, take it into the game,” Lagares said.

Team officials have come to appreciate Lagares’ willingness to learn and absorb new ideas. That doesn’t guarantee he will improve his plate discipline, but it is an important first step.

“He’s really bought into some of the stuff Kevin and Pat are doing, and I think it’s really helped him,” manager Terry Collins said. “The visualization stuff they are doing has really helped. I haven’t ever seen him swing the bat this good. It doesn’t seem like he’s fooled by anything.”

Lagares’ big spring has complicated the decision of where he should hit in the lineup, but Collins considers it a good dilemma to have.

One possibility the manager is considering — he could experiment with it as soon as Friday — is batting Lagares ninth in the order, behind the pitcher. Such an alignment theoretically would increase the RBI opportunities for the top of the order.

But Lagares also has been a candidate for the leadoff spot, along with Curtis Granderson.

“I really don’t think about that,” Lagares said about his place in the lineup. “Whatever they do with me, I just want to be out there and help the team and be part of the lineup.”

Lagares batted leadoff in 38 games last season, but mostly was sixth or seventh in the batting order.

Long said he isn’t as concerned about where Lagares hits as much as his approach.

“We’ve already got the data, and the data shows he’s homing in on the strike zone, and that makes him a more dangerous all-around player,” Long said. “You can see his confidence is building and things are going real good for him right now.”

Where can the Gold Glove center fielder take his offense?

“Numbers?” Lagares said. “I can tell you I am going to play hard every day like I always do. The numbers, God knows.”