One is a lock for the big house for the 2017-18 Boston Bruins season. Another is unlocking the necessary keys to join his former teammate on Commonwealth Avenue with new addresses on Causeway Street.

While the first game of the season at TD Garden was highlighted by David Pastrnak’s debut since signing a six-year contract at $6.67 million per, and defenseman Brandon Carlo’s returning for the first time since suffering a concussion in the team’s 2016-17 regular season finale vs. Washington, the subplots were many. And mostly about the youth movement in Black and Gold.

Billed as a “can’t miss” to make the jump after just two years at Boston University, former Terrier defenseman and former first-round draft pick Charlie McAvoy, made an immediate – and lasting – impression last April when he played six playoff games as his baptism under major NHL fire. All McAvoy did was light it up as one of the best players on the ice in Boston’s six-game loss to Ottawa in the first round.

Will Stockholm native Jakob Forsbacka Karlsson follow suit? The highly regarded BU forward followed McAvoy’s dotted-line commitment to turn pro just four days later on April 2, suiting up for his only NHL game in the Bruins’ regular season finale against the Capitals after putting up a 14-19-33 in 39 games at BU last season; 63 points in 78 career games.

Tuesday night, “JFK” made his second pro appearance at TD Garden.

Off the Bruins’ 3-2 win Monday night in Quebec City against Claude Julien and the Montreal Canadiens, B’s coach Bruce Cassidy had Forsbacka Karlsson in the lineup against the Red Wings at center between David Backes and Ryan Fitzgerald.

No shortage of competition for JFK and his fellow forwards to make the big jump.

Some traveled up and down Rt. 95 last season, hoping to stick then and now. A deep pool of draft picks is young and talented. At the other end, a grizzled veteran of NHL campaigns looking to extend a career.

The first group is headlined with Austin Czarnik, Sean Kuraly and Anton Blidh who made Black and Gold appearances last season. Add the current crop of draftees such as Notre Dame’s Anders Bjork, Boston College’s Fitzgerald, and the 2015 first round trio of Jake DeBrusk, Jakub Zboril and Zach Senyshyn. The graybeards led by former UMaine standout Teddy Purcell with a tryout invite by GM Don Sweeney after 571 career games with four NHL teams.

Bjork had a goal Monday night. Fitzgerald got Boston on the board first Tuesday night; Heinen the second – with a JFK assist. Czarnik’s penalty-shot tally at 17:19 of the second period the exclamation mark in the 4-2 final to push the Bruins to 2-0-0 in the preseason. Purcell had the final goal late in the third.

“He made a heck of a play on the goal,” Cassidy said about Forsbacka Karlsson’s assist. “I think again, we talk about JFK’s game, it’s very cerebral, he’s smart. We liked his position. It’s just about making his decisions quickly and when it’s his turn to be assertive, engage. That’s what we are going to ask him to do defensively. Make plays with the puck when they’re there. Like a lot of young guys, I think he wants to try to be mistake free. Sometimes there is a bit of tentativeness when you have that mentality, which is ok, we are just trying to get him to be – free him up – let him play. That’s what training camp is for. But he’s a good young player, and we’ve got a lot of them.”

JFK’s first period included five shifts of 3:56 playing time with two blocked shots, and one win and one loss in the faceoff dot. He ended the second period – and the game – with 8:37 played, a 4-2 faceoff ratio and a plus-1.

“I know the kind of player he is,” McAvoy, who played 23:35 with a plus-1, said about Forsbacka Karlsson. “He’s obviously a great player and had a phenomenal game. Played great until that unfortunate play. He had a great pass, back door. He’s just such a responsible centerman.”

“He went into the boards late in the second,” Cassidy said about JFK missing the final 20 and postgame interviews. “He’s day-to-day, upper body. I think wanted to – did come back and try – I don’t think it’s serious but I can’t speculate. It didn’t look good, but I don’t think it’s as bad as it looked. Again, we’ll know more tomorrow.”

Thursday, the Flyers come to town. When asked the final determiners of who makes the grade during the next 10 days, Cassidy said: “Who is hard on the puck? Who is winning pucks? Who can keep their pace up? I think they are all capable of making plays, the young skilled guys, you can probably list seven or eight that have talent and could make NHL plays. Who can play against the men, and compete and win the pucks.”

“We wanted to strengthen our depth and have that option for us,” Sweeney told the Boston Herald in April about signing JFK as another piece of his youth movement. “We really like the player and he made a difficult decision to come out. We feel confident that he could [make an impact].”

Jakob Forsbacka Karlsson is looking to play Thursday, accomplish more of those determiners – and make an impact beyond.