Exactly how long Bruce Cassidy decides to stick with his newly reconfigured lines is anyone’s guess. The Brad Marchand-Patrice Bergeron-David Pastrnak unit has been such an explosive weapon for the Bruins the last few years, it will be very tempting to go back to it quickly if the new units don’t immediately click and a game’s result is hanging in the balance.

But at least to start on Thursday, when the B’s are scheduled to play the New Jersey Devils in their first Garden game since Jan. 28, Cassidy will try Jake DeBrusk in Pastrnak’s customary spot next to Bergeron while Pastrnak will move to the line with center David Krejci and left wing Nick Ritchie.

And as much success as Pastrnak has had with the Bergeron line, whenever he gets the chance to play with his countryman Krejci, he always seems to get an extra bounce in his step.

“He’s underrated as a playmaker. His vision on the ice is unbelievable, his patience in the game is great,” the 24-year-old Czech said on Tuesday of Krejci. “Even when I was hurt earlier this season, watching it from up top, it seems like he has so much time and he makes it look so easy when he has the puck on his stick. It’s the way he is and how patient he is. He’s been unbelievable and a great mentor to me. It helps that we are from the same country. I’m excited to play with him on the wing.”

After starting the season late due to offseason hip surgery, Pastrnak exploded out of the gate. He scored five goals in his first three games and had 19 shots on net in those three contests. He has slowed down since then, going four games without a goal, and though he picked up two assists in the B’s loss on Long Island on Saturday, he has just one shot on net in his last two games.

He aims to rectify that situation with his new assignment.

“I love playing with Krech,” said Pastrnak. “He’s an unbelievable playmaker and we’ve built some chemistry over my first couple of years and we’ve become real good friends. I know what to expect from him. I need to be ready. I need to shoot all the time and we have a great chemistry together, so it won’t be a hard transition for me. For us, it’s going to start in the D-zone. We are both obviously offensive players but starting in the D-zone so we have the pucks on our sticks. And once he has it, I’m going to be ready to shoot it. Even from the red line.”

Pastrnak said the move from Bergeron’s side to Krejci’s calls for some slight alteration to his game.

“With Bergie and March, it’s a really fast game. You get on the forecheck, try to steal some pucks and get some quick play on the net. And obviously it’s been working for us,” said Pastrnak.

“With Krech, it’s a little bit different. He slows the game a little bit and gives the winger — or me — a little bit of time to pick up a little more speed. That’s the things I know when Krech gets it and maybe a couple of feet ahead of me or behind me, all I need to do is be ready for the puck or pick up the speed.

“It’s a little bit slower game but it’s absolutely no problem. I have chemistry with all three guys. It’s a little different game, but I like both. It’s a good change any time the lines get mixed up. (DeBrusk) has a great opportunity. I think he’s been playing really good and hard when I was hurt and he was on their line. Hopefully it’s going to be fun.”

For Krejci, it had seemed like the B’s eternal search for his right wing had finally ended when Ondrej Kase was obtained, but Kase has been out since the second game of the season with a suspected concussion. He’s just now skating on his own. The veteran is more than happy to get some playing time with the effervescent Pastrnak.

“We feed off each other pretty well. Obviously, he’s one of the best players in the league. Who wouldn’t want to play with him? I’m excited,” said Krejci. “He can do it all on the ice. I’m just going to try to do the best for him defensively and once we get the puck our offensive skills and instincts take over. It starts in the defensive zone, take care of our own end, play with the puck as much as we can. Most of the time he has the puck, good things happen.”

Lindholm had his reason to head home

Cassidy said a number of factors went into Par Lindholm’s desire to go back home to Sweden. After Lindholm cleared waivers on Monday, the B’s terminated his contract so he could sign with his former Swedish Hockey League team Skelleftea.

“He had a baby just before we went in the bubble or just after. I think being away from his family was tough for him to get motivated every day for practice knowing that he was an extra guy and may or may not get in. I talked to him on Sunday about it and that was basically his feeling,” said Cassidy.

“We were honest with him from Day One. We said, ‘Listen, we’re going to look at some younger guys. We’re trying to get a little bit of a different mix. (Trent Frederic) is a guy who’s put in his time in Providence. He’s a bigger body and different style and we’re going to give him a chance. So it’s going to come at the expense of you.’ ... And he knew that up front. He was not disappointed in us in any way. He just felt to get motivated every day to practice it was hard for (him) when he missed his family back home. That was his decision and we respected it. We lose some depth and he’s a good guy. He’s low maintenance and came to work every day. But we have (Greg) McKegg and maybe there’s another opportunity for a guy in Providence down the road to step in if need be.”

Odds and ends

Cassidy said that he doesn’t expect either Jakub Zboril (upper body) or Matt Grzelcyk (lower body) to be ready for Thursday’s game against New Jersey...

The Bruins game against the Devils that was originally scheduled for Monday will now be played on March 7 (5 p.m.) at the Garden. The B’s-Flyers game that had been scheduled for March 7 must still be rescheduled. The Bruins-Capitals game scheduled for April 10 will now be played April 11 (7 p.m.) ...

Spare goalie Callum Booth took a Sean Kuraly shot up high to the collarbone and went down in pain. He had to leave practice, but Cassidy said he was OK...

Craig Smith did not take part in the optional skills practice on Tuesday, but Cassidy believes he’ll be ready for Thursday’s game.