The Bruins’ roster is starting to shape out entering the final days of camp

A lineup change born out of necessity following Taylor Hall’s injury may actually start the season together.

With Hall labeled as week-to-week with an upper-body ailment sustained during Saturday’s exhibition against the Flyers, Bruins’ coach Jim Montgomery formed an all-Czech line featuring Pavel Zacha, David Krejci and David Pastrnak. The trio shined in their first action together Wednesday night against the Rangers as all three netted timely second-period tallies in Boston’s 5-4 triumph.

Jeremy Swayman went the distance stopping 28 of 32 New York shots.

Jake DeBrusk notched a first-period goal to even things up at 1-1 — about two minutes after the first of two Mika Zibanejad’s markers — banking home a rebound past former teammate Jaroslav Halak with assistance from fellow linemates Marc McLaughlin and Jack Studnicka.

Mike Reilly put the Bruins ahead for good after countering Kappo Kakko’s second goal of the night with a slick wrist shot following an initial shot fake.

Important roster decisions await Montgomery and the coaching staff. Yet, a handful of players featured on Wednesday’s roster advanced their cases for an opening night roster spot.

Here’s what we learned in Boston’s second to last preseason tilt.

All-Czech trio produces initial results.

Perhaps Montgomery and crew may alter his initial lineup from the start of camp.

If Wednesday proved anything, the Bruins might find themselves with a different-looking second line filled with skilled Czechs.

“It was pretty impressive. Hust the chemistry they seem to have right away was good,” Montgomery told the media of Zacha, Krejci and Pastrnak. “They made a lot of plays in all three zones that led to goals.”

The all-Czech trio took over in the second period, combining for three goals and five assists. Each of their goals started in transition, beginning with Zacha converting on a breakaway after intercepting a feed from the blue line just 38 ticks in.

Pastrnak’s one-timer from a tough angle off Krejci’s feed tied things up at 3-3 at 8:09.

Krejci completed the Czech trick after nudging Pastrnak’s feed past Halak to give the Bruins their first lead of the night at 15:46.

Boston’s top line on this night had the Rangers on their heels. In 14:39 of 5v5 time with Zacha, Krejci and Pastrnak, the Bruins held a 16-5 edge in shot attempts, 10-3 advantage in shots on net and outscored the Blueshirts 4-0.

The trio capped off the night with Pastrnak feeding Reilly for his game-winning tally at 12:10 of the final frame.

Reilly showcasing early urgency throughout camp

Entering camp, Reilly found himself at a bit of a crossroads. He’s a prime trade candidate with the impending salary cap ramifications once Brad Marchand, Matt Grzelcyk and Charlie McAvoy return to the lineup. Yet, he also needed a solid string of preseason outings to either solidify himself on Boston’s back end or up his stock for other potential suitors.

At the very least, his value has ticked upward during these last few weeks.

Reilly once again proved his worth on Wednesday after producing the game-winner following a nifty shot fake and subsequent wrister past Halak.

Like Marchand (hips), Grzelcyk (left shoulder), and McAvoy (right shoulder), Reilly underwent off-season surgery to repair a nagging ankle injury. Reilly came into training camp eager to put the previous 18 months of his mixed Boston tenure behind him.

The Bruins envisioned Reilly as a reliable secondary offensive option on the blue line under Bruce Cassidy. In the past, he opted to make a perfect pass over an opportunity to shoot the puck when prompted. On Wednesday, Reilly displayed a shot-first approach — even with an altered route — in another timely moment.

McLaughlin and Studnicka are inching closer to a fourth-line spot

The unique preseason line combinations provide significant opportunities for players on the cusp of a roster spot. Sometimes, candidates for bottom-six minutes encounter an extended role on the top two lines amid talent evaluations.

On Wednesday, Studnicka and McLaughlin found themselves in a similar position skating with DeBrusk in a de facto second-line assignment. They wasted little time in making an impact as Studnicka and McLaughlin set DeBrusk up for the first-period equalizer.

The Bruins risk losing Studnicka on waivers if he doesn’t claim a roster spot. Despite some setbacks over the last two years in his development, the 2017 second-round selection has stood out among other fourth-line candidates like Nick Foligno, Tomas Nosek and Chris Wagner.

McLaughlin has picked up where he left off following his initial stint with the big club following a successful four-year career at Boston College. Barring injury or an unforeseen development, the Billerica native will likely appear on the fourth line depth chart to start the 2022-23 campaign.

A.J. Greer’s performance throughout camp — highlighted by his two-goal outing last Tuesday against the Rangers — makes him another prime candidate.

The Bruins may have a better idea of their fourth-line outlook come Saturday’s preseason finale against the Devils. Given the camp performances, the Bruins may have a unique trio of McLaughlin, Studnicka and Greer.