BOSTON — Bruce Cassidy didn’t like what he was seeing out of his middle six Tuesday night.

During the second period of their eventual 5-2 loss to the Calgary Flames at TD Garden, the Boston Bruins head coach revamped his second and third lines in hopes of finding some sort of jump.

He started with Jake DeBrusk, David Krejci and Karson Kuhlman as the second unit, with newcomer Nick Ritchie, Charlie Coyle and Anders Bjork forming the third. Upon changing things, he rolled with Coyle, Bjork and DeBrusk together, with Ritchie bumping up (or down, depending on how you want to look at it) to Krejci and Kuhlman’s line.

Cassidy indicated he felt there were a lot of passengers in the loss, and ultimately shared why he elected to turn on the blender.

“I didn’t see much energy, much offense, much willingness to recover pucks,” Cassidy said. “The Coyle line had a rare off night. They were just fighting it, so you try to kind of mix it up a little bit. Krejci and DeBrusk haven’t produced a whole lot lately, so it’s just get a guy away from a guy for a while, see if it loosens them up. Sometimes it works. Tonight, it did not.”

The Ritchie-Coyle-Bjork line was a disaster, with a Corsi for of one and Corsi against of five in just 4:57 ice time. Once Ritchie moved to Krejci’s line things got a little better, with that trio posting fives in both Corsi for and against.

It’s going to take Ritchie some time to find his way in the Bruins’ lineup, so he can be forgiven for some missteps. But with Ondrej Kase likely to begin with DeBrusk and Krejci, something is going to have to give with Ritchie on the Coyle line.

Here are some other notes from Tuesday’s Bruins-Flames game:

— For the second time this season, Chris Wagner has scored goals in consecutive games.

The fourth line right winger gave the Bruins some life late in the third period. With the Flames mostly controlling play and the arena library quiet, a nice net drive from Sean Kuraly resulted in a scramble in front of the net and ultimately Wagner, from his belly, swatting in a puck past a sprawled out David Rittich.

It was a textbook greasy, fourth line goal, but one Wagner certainly will take.

“I don’t know what (Rittich) was trying to do,” Wagner said. “I think he fell over and was just hanging on for dear life. But that happens in front of the net, people are flying everywhere and just want to try to whack the puck.”

— While the middle six was getting mixed up, the fourth line, for a change, was stable.

With Wagner and Kuraly on the wings and Par Lindholm between them, the fourth line arguably was Boston’s best all night, even before Wagner’s goal.

Lindholm, playing in his 100th NHL game, did a nice job of driving the line, especially for a guy that hadn’t gotten into a game since Feb. 9.

“I thought tonight we played pretty well,” Wagner said. “We started a lot of shifts in the D-zone but got into the offensive zone a good amount too. We had some good spacing, some good puck possession. But yeah we’ve had different guys in there at certain times, so we’re just trying to find the right line and try to be consistent every night.”

Over the last few weeks there has been some variation of Wagner, Kuraly, Lindholm, Anton Blidh and Joakim Nordstrom on that fourth line. That unit hasn’t had a similar impact to what it was able to provide last season, so for the time being the Kuraly-Lindholm-Wagner group probably deserves an extended look.

— Brad Marchand is on a seven-game point streak (2-8-10), and extended a club record of his Tuesday.

The top-line winger had a shorthanded goal in the first period, good for his 27th shorty of his career. Since he already holds the franchise record in PK goals, he’s simply extending his record.

— The Bruins owe some thanks to the Toronto Maple Leafs, who held on to a 4-2 win over the Tampa Bay Lightning on Tuesday.

As a result, Boston still is five points clear atop the NHL standings, though the Bolts do have a game in hand.

Thumbnail photo via Winslow Townson/USA TODAY Sports Images