Then, after starting the season without Wideman, the Bruins lost more back-end mobility. On Nov. 29, they traded Matt Hunwick to Colorado in a salary dump to clear space for Marc Savard. No. 6 defenseman Adam McQuaid and rookie Steven Kampfer have served as replacements for Wideman and Hunwick.

Julien needed a top-flight right wing to replace Phil Kessel. Management acquired Nathan Horton, the ex-Panther they identified as having the characteristics they required. In doing so, Chiarelli sacrificed Dennis Wideman, the team’s sharpest puck-moving defenseman.

But the 2010-11 Bruins have been assembled in accordance with that vision by a GM who concurs with Julien’s philosophy and presented him with the charges he’s coaching.

Dismissing Julien now would be out of character for Chiarelli and the rest of the management group, one that shares responsibility for the slide down the standings. Julien’s defense-first system may be passive, unimaginative, and easy to play against when players are underachieving and the team is slumping. For the most part, Julien rolls four lines and feeds ice time to players who may not be deserving of minutes.

“Right now, my job is to coach this hockey club,’’ Julien said after yesterday’s tuneup at Ristuccia Arena. “Whatever’s being said out there or whatever goes, that’s out of my control. I come in every day with the same intentions, and that’s to coach this hockey club and make this team as successful as I can. That’s the way it goes. That’s the nature of the beast. We all know that as coaches. It comes around every once in a while.’’

Then again, at the tail end of 2006-07, Chiarelli said Dave Lewis was safe. In June, Lewis, after completing only one season in a four-year contract, was fired. Julien is in the first season of a multiyear extension.

“That’s my preference and that’s my recommendation,’’ Chiarelli said, when asked if Julien would not be fired this season. “This is a collective thing that we do on these matters. I have full confidence in Claude and his staff to figure it out.’’

When teams fall so short of the standards they’ve set, responsibility usually falls upon coaches’ shoulders, sometimes at the cost of their employment. Such a fate is not likely to fall upon Julien. Yesterday, when asked about Julien’s job security on 98.5 The Sports Hub’s “Toucher & Rich,’’ general man ager Peter Chiarelli gave his coach his endorsement.

The Bruins are parked in a funk that’s seen them drop four of their last five games, the most recent a no-heartbeat, 3-0 setback to Anaheim on Monday. For too many of those minutes, the Bruins played a zero-resistance style.

For now, Scott Gordon is the sole member of an infamous club — NHL coaches sacked in 2010-11 — that may grow to include the likes of John MacLean, Ron Wilson, Brent Sutter, and/or Todd Richards.

During the offseason, the Bruins projected David Krejci to develop into a No. 1 center. Krejci’s emergence, combined with the eventual selection of Tyler Seguin, prompted the front office to shop Savard leading up to the draft.

Horton is scoreless in the last four games. The flat-footed defense gave up 26 third-period shots to Washington last Saturday, indicating how it struggles to retrieve pucks. Krejci has been taken away from Horton and Milan Lucic and dropped to the third line.

So as much as Julien might be culpable for the December gloom, it’s been a top-to-bottom failure that the Bruins must turn around starting tonight against Atlanta.

“It will be nice right before Christmas and right before heading out on a road trip,’’ Julien said of a better showing. “And feel good about ourselves again. I think that’s the main thing. Winning always seems to cure those kinds of situations. It will be nice to see that and get rewarded against a pretty good team that’s been playing pretty good hockey lately.’’

Yesterday, for the second straight day, Julien rolled out lines he first introduced on Tuesday. Savard centered Lucic and Horton on the first line. Seguin and Mark Recchi flanked Patrice Bergeron on the No. 2 line. Krejci centered Blake Wheeler and Michael Ryder on the third unit, while the fourth line of Daniel Paille, Gregory Campbell, and Shawn Thornton remained the same. Brad Marchand (undisclosed injury) didn’t practice and is considered questionable for tonight.

They’ll square off against an Atlanta club led by Julien’s former right-hand man. Craig Ramsay, Julien’s lead assistant for the last three years, has helped to transform a lifeless organization into a playoff contender. Ramsay’s most significant asset is his blue-line six-pack, led by forward-turned-defenseman Dustin Byfuglien, who had a hand in all four goals in a 4-1 win over the Bruins Nov. 28. Ramsay gives Byfuglien and the rest of the defensemen a perpetual green light to carry the puck and join the attack. As a result, the Thrashers average 3.22 goals per game, good for the league’s No. 5 offense.

In comparison, Julien’s D-men do not join the rush as often. But overall, they don’t have the fleet feet of Byfuglien, Tobias Enstrom, Zach Bogosian, and Johnny Oduya. Overall team speed — namely, the lack of it — has been one of the Bruins’ biggest issues.

To address that concern, the Bruins spent most of yesterday’s practice working on their transition game. The idea is to generate speed at center ice and carry enough momentum into the offensive zone that opponents can’t slow them down without taking penalties. Two days earlier, practice emphasized battle drills and overall competitiveness to jack up the team’s pulse.

The practices were Julien’s way of turning around a team that has been too slow and too soft.

“Those are the two things we really feel we needed to get better at, our battle and putting more emotion into our game,’’ Julien said. “At the same time, today was about our transition game and trying to get some speed and getting a better attack. Hopefully those two combined together, if we can do it well, can give us the results we want.’’

Fluto Shinzawa can be reached at fshinzawa@globe.com.

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