Mason Lohrei may still have the face of a teenager, but from the neck down, he’s starting to look more and more like a National Hockey League defenseman.

The Bruins’ young defenseman left a good impression on everyone with the way he rose to the occasion when he was thrown into the playoff mix because of injuries last spring. And that experience gave him a taste for more.

While he’s still got to solidify his spot on the roster, something he’s quick to point out, the 23-year-old appears to be putting his best foot forward. The lanky 6-foot-5 blueliner added about seven pounds in the offseason, up from 212 pounds at season’s end to 219, and he is one of the first young players back working out at Warrior Ice Arena in the summer.

Though some players hold off till mid-summer before getting back on the ice, Lohrei took only 10 days off of the blades. He went home to Madison, Wisconsin for a brief respite before heading back to his old prep Culver Academy in Indiana to skate, work out, and occasional play pickle ball before heading back to Boston.

His playoff performance was a nice surprise for everyone, but Lohrei hopes that’s just the start of something big for him.

“Being able to go out there and play with confidence and have that trust from my teammates and the coaching staff, it’s huge. That’s what it was. It was just me going out there and playing,” said Lohrei after a skate on Tuesday. “Obviously, it didn’t end the way I wanted. I felt good about my play but there were still some things I wish I (did better). I always want to make more of an impact, no matter what happens. If we’re not winning… I want to help us win more. It was definitely a boost of confidence, but it just made me a lot hungrier. It just makes me want it more.”

With his first pro season under his belt, in which he played 41 regular-season NHL games plus 11 playoff games, Lohrei wants to continue climbing up the mountain to where he wants to get.

“I’d say I have high goals for myself. Last year I wanted to come in and show that I deserved to be on this team and do that throughout camp. This year, I’ve gotten a taste and I want to show them what I can do,” said Lohrei, who’s been working on improving his initial burst.

“I want to be a top defenseman. I want to go and show that I’m making steps to be there one day. It doesn’t happen overnight, right? But I want to show that it’s slowly coming along. That’s what I want to be in this league and for this team.”

Last season was a year of adjustment for Lohrei. His offensive skills are obvious and impressive, but it takes more than flashiness to be an effective NHL defenseman. He’ll most likely always be an offensive-minded player but he learned last year that you have to bring a certain hardness to your game on each shift. And you have to know when to keep it simple.

“When you get older, it’s second nature. But when you first come in, it’s not second nature. As the year went on, it definitely became that way,” said Lohrei. “(Captain Brad Marchand) was really good about harping on me about that stuff, just being hard and simple and making the right play. You definitely learn. But it’s like anything, you’ve got to do it before you can get good at it.”

Lohrei will also be working with a new position coach, Jay Leach. The two had an opportunity to meet after Leach was hired in June.

“We talked for a while and I’m really excited to work with him,” said Lohrei of the former Providence Bruins coach. “Obviously I’ve heard a lot from guys and no one’s ever said a bad thing about him. He’s going to bring good energy and I’m going to be pumped to learn from him.”

Lohrei has high expectations for himself. It sounds like he’s ready to put the work in to meet them.

SWAYMAN UPDATE: Neither Boston nor goalie Jeremy Swayman elected to go to arbitration this summer, and both sides have said several times that they are confident a long-term deal will get done. Now nearly halfway into August, nothing has been announced with training camp fast approaching.

Bruins CEO Charlie Jacobs provided a minor update about where things stand with the team and the goaltender.

“I try not to comment on player personnel contract negotiations. We are still negotiating with Sway,” Jacobs said during a radio appearance. “I hope that he’s ready to play come training camp. We have some things to work out. I’m sure we’ll get there.”

The Bruins traded Linus Ullmark to the Ottawa Senators in June and acquired Joonas Korpisalo. The goalie did not have a good season in Ottawa and statistically was one of the NHL’s worst goalies. Boston also has Brandon Bussi in Providence, who’s knocking on the door of an NHL debut.

Swayman is coming off a strong 2023-24 season that saw him play in all but one playoff game for Boston through two rounds. He finished the regular season with a 25-10-8 record with a 2.53 goals-against average and a .916 save percentage.