Aaron Boone said he saw it in spring training.

Willie Calhoun was looking every bit like the player who was productive earlier in his career with the Rangers.

“This guy’s healthy and in a good place, there’s no question in my mind he can really hit,” the Yankees’ manager recalled thinking. “He hit all spring.”

Nobody knew at the time how important Calhoun would become.

He earned a promotion on April 8, and has become a mainstay in the lineup due to injury and underperformance around him.

Saturday night, he found himself in the third spot in the batting order — usually reserved for one of the top batters on a team — and hit the go-ahead home run in the Yankees’ 3-1 win over the rival Red Sox at the Stadium.

“Every single day, you just come to the park and try to have that confidence and edge to you every single day you walk through the doors,” Calhoun said. “Right now I’m feeling pretty good. Try to keep that rolling.”

Calhoun entered the contest posting a slash line of .244/.316/.403, with four home runs and 15 RBIs in 119 at-bats.

Boone said he has swung even better that, frequently hitting into tough luck.

The well-traveled, 28-year-old Calhoun has performed better as his role has expanded.

He sported an .805 OPS in May, when he saw somewhat regular playing time, and reached base in 15 of his last 18 games. It has only increased in June, and Boone hit him leadoff before slotting him third on Saturday in place of the resting Anthony Rizzo.

“I want some balance in the lineup, and with Rizzo being out tonight, for me it was easy to put him in there,” the manager said before the game.

In the bottom of the sixth with the score tied 1-1, Calhoun smoked a 1-2 splitter knee-high over the fence in right-center field for his fifth home run of the year.

Calhoun is on pace to shatter his career-high of 309 at-bats set in 2019.

He has dealt with a number of injuries in recent years, most notably a fractured jaw in 2020 after he was hit by a Julio Urias pitch while a member of the Rangers.

He only appeared in 22 games last year while splitting time with the Rangers and Giants, but he appears to have found a home in The Bronx after he signed a minor league contract in December.

“It’s been pretty crazy, honestly,” he said. “The last year, really. Kind of just put that all in my rearview mirror. This year has been unreal so far.”