Mets prospect Dominic Smith isn’t making the best first impression on new manager Mickey Callaway.

Callaway scratched Smith from the starting lineup for the Mets’ first spring training game Friday after the first baseman showed up late for team meetings. Smith had been slated to bat cleanup in the game against the Braves.

The Mets’ new skipper called it “a little shocking” Smith would be late on the first day of games.

As for Smith, he initially wouldn’t reveal why he’d been scratched but eventually talked to reporters at the urging of Mets PR staff.

“Everybody wants to know why I wasn’t in the lineup today. I was late. I apologize,” Smith said (via the New York Daily News). “That’s stuff that shouldn’t happen. It’s unacceptable in any locker room, the Mets or wherever you play.

“I am not in there today, just something that won’t happen again.”

The 22-year-old Smith, considered the No. 2 prospect in the organization in 2016, struggled in his MLB debut last season, slashing .198/.262./.395 in 167 at-bats, although he flashed some power with nine home runs. According to the Daily News, he’s slated to begin 2018 at Triple-A Las Vegas.

So Smith knows Friday was a missed opportunity. He admitted he’s disappointed in himself.

“I am more upset I let myself down. I was so excited last night to be in the lineup and be playing and stuff like that. It’s the first day, you are a little kid inside,” Smith said. “Sometimes you can’t get sleep. Up all night, thinking, ‘Oh my God, it’s my first day again. Get to show what I can do.’ I am kinda more disappointed in myself and with myself than anything else.”