Hugo Gonzalez sported a large scratch on his neck when he addressed the media after Wednesday’s Celtics practice — and maybe a few mental scars from an ugly sequence two nights earlier.

Late in the third quarter of Monday’s 112-105 loss to the Pistons, Gonzalez was beaten for a layup off a sideline out-of-bounds, then turned the ball over on the ensuing possession, leading to a fast-break dunk for Detroit. After those back-to-back miscues, the 19-year-old rookie — who’s had an otherwise encouraging start to his NBA career — watched the rest of the game from the bench.

“That wasn’t a great sequence,” Gonzalez said. “It was really tough to have it, and even tougher to see it again (on film). But you’ve got to learn from that and move forward.”

Gonzalez’s errors occurred while Boston was utilizing an all-wings lineup that it hadn’t shown previously. Head coach Joe Mazzulla subbed Gonzalez in for point guard Anfernee Simons with 33.5 seconds left in the quarter, deploying him alongside Jaylen Brown, Jordan Walsh, Baylor Scheierman and Josh Minott.

With no guards on the floor, Gonzalez brought the ball up after Jaden Ivey’s layup, and Caris LeVert picked his pocket just past halfcourt.

The Celtics’ personnel usage put Gonzalez in a tricky spot, Mazzulla acknowledged, but didn’t excuse either of his miscues.

“I mean, losing the ball at halfcourt, that’s a tough one,” Mazzulla said Wednesday. “You have to learn how to be able to obviously handle the ball, but we take Ant out for Hugo on the last possession of the quarter, knowing we’re getting the ball back, and so you only have one ball-handler on the court in Jaylen and everyone else isn’t one. So that’s a little bit of a tough situation. As you grow, you just can’t allow that to happen.

“But coming in on a defensive possession, (it’s about) just having a clear understanding that your role is to be a great defender, regardless of if it’s at the start of the game or when you step into the game. Just making that clear and then working towards being able to do that regardless of the situation. We worked on that today, and those guys, they want to get better.”

Visibly frustrated after his blunders, Gonzalez received a pep talk from veteran guard Derrick White once he reached the Celtics’ bench. White’s message?

“Stay with it,” White said. “Obviously, he’s hard on himself and (had) a tough couple of possessions, but it’s a long season, long game. Just understand it’s going to be those ups and downs, and just know that I’ve been there and just trying to have his back.”

Gonzalez, the Celtics’ youngest player, appreciated the words of support.

“It means a lot,” Gonzalez said. “A player like Derrick is an incredible player and also an incredible person. Really great teammate, always looking for the guys next to him, and especially me — he has helped me a lot. And those type of moments, they just show the type of person and the type of player he is on and off the court.”

It was a teachable moment for the Real Madrid product, who’s carved out a role this season with his aggressive defense and hustle plays at both ends.

The first Celtics rookie to see regular playing time since Payton Pritchard and Aaron Nesmith in 2020-21, Gonzalez has appeared in 21 of Boston’s 26 games, including each of the last seven. He ranks second on the team in individual net rating behind starting center Neemias Queta. In the loss to Detroit, he tallied five points and five rebounds and was a plus-9 over his 16 minutes.

Gonzalez, whose neck scratch was the result of an especially physical Celtics practice, will look to bounce back when Boston hosts the Miami Heat on Friday night at TD Garden (7 p.m.).

“Everybody makes mistakes,” he said. “I’ve just got to try to make less mistakes as I can. That’s my objective.”