The concern seems silly now, worrying about Aroldis Chapman’s fastball velocity. Aaron Boone laughed about it, because of what he has seen since the spring, how his closer has alleviated doubts with a brilliant start to his season.

“Any time we don’t see 100 or 100-plus [mph] out of Chapman, it’s a story, which is a little bit funny,” manager Aaron Boone said Tuesday before the Yankees hosted the Padres. “If he’s 96 or 97, it’s like, ‘Is he OK?’ ”

Early on this season, there were questions. There were worries. The 31-year-old Chapman’s fastball wasn’t living in the triple digits — his velocity in the mid-90s, unheard of for the pitcher nicknamed the “Cuban Missile.” That seems like a lifetime ago, with Chapman not only averaging 99.5 mph per fastball, according to BaseballSavant.com, but owning the ninth inning again.

Healthy throughout the spring and so far this season, Chapman is in the midst of another terrific campaign in what has been a mostly brilliant career.

The five-time All-Star’s 1.66 ERA and 0.92 walks and hits per innings are his lowest since 2016. He’s striking out more than a hitter per inning — 32 in 21 ²/₃ frames — and has converted 15 of a possible 16 save opportunities.

Chapman has been even more dominant lately. Over his past 14 appearances, he has a 0.71 ERA and 20 strikeouts over 12 ²/₃ innings. The opposition is batting just .116 off him. Until Manny Machado’s double in Monday’s victory over the Padres, Chapman had produced five straight hitless outings.

“I’ve just felt like he’s been healthy since spring training. I felt his work in spring training was really good,” Boone said. “I feel like he’s gotten in a groove here lately where his command has been really good. He’s been filling up the strike zone really well.”

Most impressive, Chapman has walked only six batters so far after walking 30 a year ago, equal to a 14.2% walk rate. That number is down to 6.9% this year, the best of his Yankees career. Part of that decrease has been the result of using more pitches, throwing his slider more (28.8%).

It’s a pitch he controls well and has honed.

“We saw it last year become a more important pitch for him. Now it’s an absolute factor,” Boone said. “The other day when he lost his command a little bit with his fastball, he kind of leaned on his slider to get himself righted again. It’s been a really good weapon for him.”