Maybe it’s fresh legs. Maybe it’s a newfound spirit. Maybe it’s dad strength.

Whatever the source, Josh Donaldson had a special day Saturday in his first game as the father of a newborn girl, which is a good sign for the Yankees, who need his bat to be reborn.

The third baseman blasted his 13th home run of the season — an inning after coming up inches short on a bid for a three-run homer — in the Yankees’ 10-3 win over the Rays in The Bronx.

Donaldson, who went on the paternity list Wednesday so he could be with his fiancée to welcome daughter Lily into the world, missed four games and returned with a loud bat and plenty of energy. In the seventh inning, he made an aggressive first-to-third dash on a Miguel Andujar single to center, then scored on a wild pitch.

He was constantly smiling and he played with a zeal that backfired on a bat-flipped single.

It all was appreciated by the club, nonetheless.

“Couple days before [leaving the team] I really just made a decision: That’s what it’s going to be,” Donaldson, who has reached base eight times in his past 13 plate appearances, said of his energy. “That’s what I’m going to bring.”

In the 36-year-old’s first at-bat of the game, he stepped up with Giancarlo Stanton on second and Gleyber Torres on first in the first inning. Donaldson blasted a Corey Kluber sinker to right and let out a vicious bat flip that would have been more dramatic if the ball actually had reached the fans

Instead, it bounced off the very top of the right-field wall, and Donaldson’s 339-foot blast went for a long single — the fourth of seven straight singles in the inning — that loaded the bases during a six-run frame.

Maybe Donaldson did a few pushups between innings. He added a bit more pop in his next try.

In the second inning, Donaldson drilled a JT Chargois slider just out of the reach of leaping right fielder Manuel Margot for a solo homer to make it 7-0.

“Brought a lot of energy with him. Guys kind of fed off it a little bit,” manager Aaron Boone said. “We need that from him. He’s a premium player when he’s going.”

Donaldson finished 2-for-4 with a hit by pitch, three runs scored and an estimated 1,073 feet of deep flies, the third of which was caught on the left-field warning track. A bat that has not come around all season is showing hopeful signs.

“He’s got an edge to him for sure,” winning pitcher Jameson Taillon said. “We definitely missed it a little bit. He can definitely bring some edge for us.”

Donaldson had to talk with Boone on Monday — his last game before paternity leave — after not running out of the box on an RBI single that went off the left-field wall and ended with his being thrown out at second base.

The hustle issue has not gone away, but he would be forgiven if his bat and his passion does not go away, either.