The Bruins had understandable reasons for firing Claude Julien and replacing him with Bruce Cassidy.

Julien didn’t agree with management regarding the quality of the roster. General manager Don Sweeney had no intentions of signing Julien to an extension beyond next season. Cassidy, always considered Julien’s successor, gets a head start on preparing for 2017-18. The change sent a message to Bruins customers, forced to pay porterhouse prices for ground chuck, that the status quo required someone to be punished. 

But the Bruins also changed coaches so Sweeney, team president Cam Neely, and the rest of the hockey operations staff can evaluate players with greater clarity. 

“I felt there was a level of frustration on wins and losses and what he’d be subjected to on a nightly basis,’’ Sweeney said of Julien. “I felt we’d be in a better position moving forward to allow our players to be assessed on an individual level and for me as a general manager to be assessed on a personnel level to be making decisions going forward as to who’s part of our group.’’ 

In Sweeney’s view, replacing Julien with Cassidy might eliminate some of the noise in tracking the signal. It is an unusual declaration from the executive most responsible for determining who can and cannot play. 

Based on historical data, several players underperformed under Julien: David Backes, Ryan Spooner, and Matt Beleskey. Backes was parked on 11-11—22 at the time of Julien’s firing. Spooner had eight goals and 19 assists. Beleskey was riding a 2-5—7 line. All three of the players’ point-per-game averages are down this season compared with last season.

It’s possible and certainly hoped for, from a Bruins’ perspective, that the three players will rebound on Cassidy’s watch. Coaching changes happen with that in mind. Julien made Spooner a healthy scratch after just three games. Julien usually rolled Backes, a natural center, as his No. 2 right wing. Beleskey has taken shifts as the No. 4 left wing, one or two lines below where Sweeney expected him to play after signing him to a five-year, $19 million contract. 

Perhaps under Cassidy, all three will see more shifts, play clearer roles, and be deployed to maximize their strengths. Backes responded to his first-line promotion with a 1-2—3 performance Thursday against San Jose. 

But going from one coach to another shouldn’t necessarily be considered an opportunity with which to snap a better picture of who a player is and what he might become. A GM’s primary mandate is to identify who should be on his roster and who should be shown the door. 

One goalie coach swears he can predict how a puck stopper will play based on how he carries himself during that day’s morning skate. Whether this is an accurate measurement of future performance remains to be seen. But a GM and his scouts are employed because, in theory, they can identify who can play and who cannot better than the average puck watcher. 

Nobody gets every forecast right. But the best observers can zoom in on a player’s traits amid any other variables — coach, teammates, strength of opponents. Theoretically, an ace scout should be able to evaluate a player even if he’s playing in a snowstorm with leather skates and his stick turned upside down. 

Spooner is the Bruins’ best example of a player producing confusing data. In 2014-15, Spooner (8-10—18 in 29 games) looked comfortable near the end of the season between Milan Lucic and David Pastrnak when David Krejci went down because of a knee injury. Last season, Spooner (13-36—49 in 80 games) was most effective between Beleskey and Jimmy Hayes. There were times when Spooner’s speed, agility, and hands made him look like a less-glamorous Matt Duchene. 

This season, Spooner reported to training camp expecting to be the No. 3 center behind Patrice Bergeron and Krejci. Frank Vatrano’s preseason foot surgery, however, left an opening at No. 2 left wing. The Bruins declared that position more critical for Spooner to fill than third-line pivot. 

It has not gone well. Had the second line of Spooner, Krejci, and Backes provided close to the production submitted by the No. 1 threesome, Julien might not have gotten canned. Spooner hasn’t been a go-to offensive player. The 25-year-old, never stout on defense, has continued to be an unreliable player in his own zone. 

Cassidy cited two superstars that Spooner, as a wing, could emulate in terms of handling the puck and creating plays: Patrick Kane and Johnny Gaudreau. It would be a high standard for Spooner to reach. Kane was the No. 1 overall pick in 2007. Gaudreau has been a first-line threat since entering the league as a 21-year-old out of Boston College. 

But it is time for the Bruins to decide if Spooner is a keeper or trade bait. He will be a restricted free agent at season’s end. Regardless of how he’s played, Spooner will merit a raise from his current $950,000 average annual value, in Boston or elsewhere. 

Spooner’s usage under Cassidy, and how he responds to it, may help Sweeney and his colleagues make the decision. 

“That’s part of the evaluation process — to see what players will respond to a different voice, making some tweaks, and see if they can,’’ Sweeney said when asked who could improve under Cassidy. “Part of this is to find out whether or not some of the players that we’ve earmarked as potential guys that can complement our core group can grow into parts of the core. Torey [Krug] is a great example of a player that has sort of grown into that group. But there was a lot of unknowns about Torey a couple years ago.’’ 

At the time of Julien’s firing, Spooner had provided the Bruins with 190 games of NHL information. The Bruins have other data points to consider, such as conditioning test results, biometric feedback, and character assessments. On top of the eye test, all this information should give the Bruins a clear idea of what Spooner is and how to proceed with the center/wing. 

History shows, however, that Sweeney, Neely, and their hockey ops colleagues have missed more than they’ve hit. They signed Zac Rinaldo, Jonas Gustavsson, and Joonas Kemppainen. They acquired Lee Stempniak and Landon Ferraro. They let Brett Connolly walk for nothing. Changing coaches could help them evaluate their players with greater accuracy. If so, they’ll take it. 

NEXT STOP

Julien should have choices

Claude Julien should not be unemployed for long. Assuming the Bruins grant Julien permission to interview, he should have several choices. Julien has one year remaining on his contract. According to ESPN, the Bruins owe Julien $3 million next season. Possible destinations: 

■ Las Vegas — Golden Knights GM George McPhee has repeatedly stated his desire for a coach with experience. Julien fits that profile. However, the expansion team will not be competitive until their draft picks graduate to the NHL. Julien will turn 57 in April. It would be more of a ground-up project than the 2007-08 Bruins team he helped bring to the playoffs. While ownership looks solid, Julien would prefer a team that’s closer to winning. 

■ Florida — The Panthers are not far from being a challenger. They have young star power in Aleksander Barkov, Jonathan Huberdeau, and Aaron Ekblad. They’re stable in goal with Roberto Luongo and James Reimer. Julien would be reunited with Jaromir Jagr and Reilly Smith. Stability is always a question with the Panthers, even under new owner Vinnie Viola, because of attendance issues in Sunrise. But South Florida would not be a bad place for Julien to land. 

■ New York Islanders — Doug Weight has eased into his role as Jack Capuano’s replacement. So ownership may not be as interested in finding a full-time replacement. Meanwhile, the Islanders have trouble spots. It’s unknown whether they’ll be residing at Barclays Center much longer. John Tavares is under contract for only one more year. It looks like there’d be too many concerns for Julien to take on. 

■ Dallas — Lindy Ruff will be out of contract at the end of the year. Ruff was used to airtight goaltending in Buffalo with Ryan Miller. He’s gotten nothing of the sort with Kari Lehtonen or Antti Niemi. So while goaltending has been Dallas’s primary shortcoming, Ruff may take the fall for the Stars’ disappointing season. If GM Jim Nill lets Ruff walk and can find an upgrade in goal, Julien would welcome working with Tyler Seguin again. 

■ Vancouver — The Canucks are in a similar position as the Bruins: desperate to make the playoffs while rebuilding. Willie Desjardins is looking at his second playoff miss in three seasons behind the Vancouver bench. GM Jim Benning is familiar with Julien from his days as assistant GM in Boston. Like the Bruins, however, the Canucks are a ways off from growing back into a serious contender. 

ETC.

Offside challenge a waste of time

Chicago and Minnesota played in the league’s only game Wednesday. The showcase on NBC Sports Network served as the perfect platform to underscore the silliness of the offside challenge. 

The goal Chicago contended was Zach Parise’s tying strike in the second period. Before Parise shoveled in a net-front puck past Corey Crawford, the Blackhawks believed the left wing failed to tag up before Charlie Coyle stickhandled across the blue line. Mansfield’s Ryan Daisy was on the watch, waving his arms sideways to signal no offside on the play. 

Minutes later, Daisy was on the line with Toronto — using an iPhone, no less, instead of the hard-wire connection usually available in every rink — to discuss whether he would be merited in pulling the goal off the scoreboard. It would take Daisy and the league nearly 10 minutes to conclude what is almost always the case in such situations: Replay slowed down to dial-up speed is often inconclusive. 

The question was whether Parise, who had been in the offensive zone, got back to the blue line before Coyle settled Matt Dumba’s pass. Various angles could not determine whether the East Weymouth native had the puck on his stick before Parise tagged up. Therefore, because the replay was inconclusive, Daisy’s mandate was to follow Rule 78.7 and confirm his original call of no offside and good goal. 

“Review was not conclusive in determining,’’ the NHL said in a statement, “whether Parise had tagged up at the instant the puck touched Charlie Coyle’s stick.’’ 

Given the speed of the play and the multiple events he had to consider, Daisy was in a tough spot to make a definitive call. But that’s the nature of just about every potential offside play. It’s the definition of a hard call. It’s not possible for a linesman such as Daisy to get every one right. Even replay, with its multiple camera angles and frame-by-frame advancement, can’t make every call definitive. 

It would be one thing if replay were conclusive every time. It’s not. It’s even worse on goalie interference challenges, which are subject to referees’ interpretation more than a black-or-white decision. 

So the nature of the play — and the sport — makes the offside challenge an inexact and unnecessary exercise. It is a waste of time and resources. Nobody will miss it if it goes away. 

Change of plans

Thursday’s blizzard deep-sixed thousands of travel plans, including that of Doug Armstrong. The Blues GM attended Wednesday’s Providence-UConn game at Hartford’s XL Center to monitor draft picks Tage Thompson (No. 26, 2016), Maxim Letunov (No. 52, 2014), and Jake Walman (No. 82, 2014). Armstrong was supposed to be in Toronto for Thursday’s Blues-Leafs game, but his flight was canceled, according to ESPN. So Armstrong attended the Bruins-Sharks game at TD Garden instead. 

Dell beating the odds

Aaron Dell stands just 6 feet tall, which is miniature when it comes to today’s goalies (see 6-foot-6-inch Vezina favorite Devan Dubnyk). He was undrafted. Dell played for three seasons at North Dakota, preceding Zane McIntyre, before earning his first pro job with the Allen Americans of the Central Hockey League. He did not become a full-time NHLer until this season as a 27-year-old. But the Sharks have no complaints with how Dell has served as Martin Jones’s backup. In 10 appearances, Dell is 6-3-0 with a 2.05 goals-against average and a .928 save percentage. It’s been a punishing season for backups because of the compressed schedule. Waiver casualties include Anton Khudobin, Jonas Gustavsson, Jhonas Enroth, and Curtis McElhinney. But Dell has found a niche by being athletic, competitive, aggressive, and resilient. The Sharks are spending just $3.625 million on Jones and Dell through 2018. 

Shattenkirk unlikely in sights

The Bruins kicked the tires on Kevin Shattenkirk before the 2016 draft. But acquiring Shattenkirk would likely have cost the Bruins both of their first-round picks, used to select Charlie McAvoy and Trent Frederic, and a roster player. McAvoy’s continued development as a Boston University sophomore has lowered the likelihood of the Bruins making another go-around for Shattenkirk, who will be an unrestricted free agent after this season. McAvoy and Brandon Carlo are locks to be two of the Bruins’ three right-side defensemen in 2017-18. Colin Miller, Kevan Miller, and Adam McQuaid are in the picture, although one will probably be selected by the Golden Knights in the expansion draft. Not only would the Bruins have to cede assets to acquire Shattenkirk, they would have to sign the right-shot defenseman to an expensive extension. 

Loose pucks

On April 2, 2007, when the Devils fired Claude Julien, Jay Pandolfo was one of his players. Nearly 10 years later, when the Bruins fired Julien, Pandolfo was one of his assistant coaches. The inimitable Elias Sports Bureau does not track information on assistant coaches. So without Elias’s services, I turn to the crowd to answer who was the last ex-player/assistant to experience two firings of the same coach . . . Arizona and Colorado, teams that have acknowledged this season is a lost cause, have not reduced their asking prices, according to one Eastern Conference executive. Their demands are likely to go down before the March 1 deadline. The trade market could start to loosen once that happens . . . Jonathan Ericsson could miss up to two months after breaking his wrist Thursday. Ericsson was injured during Detroit’s 6-3 loss to Washington. The shutdown defenseman’s loss should confirm to GM Ken Holland that the Red Wings’ 25-year postseason streak will end. Moving Thomas Vanek and Brendan Smith, two UFAs-to-be, will help the rebuilding process . . . Hard to believe that it took until Thursday for Joe Thornton to solve an NHL goalie. Thornton recorded his fourth goal of the season when he snapped a puck past Tuukka Rask. His three other goals were empty-netters . . . One week later, the Toronto war room is still reviewing Julian Edelman’s catch to see if the Patriots were offside.

Fluto Shinzawa can be reached at fshinzawa@globe.com. Follow him on Twitter @GlobeFluto. Material from interviews, wire services, other beat writers, and league and team sources was used in this report.