The Bruins are still mulling the idea of a massive offer sheet for Winnipeg Jets restricted free agent defenseman Jacob Trouba, but they’re having second, and third thoughts about the bold move according to a league source.

While a seven year, $49 million offer sheet could net them the 22-year-old Trouba with a high ceiling as a possible No. 1 defenseman, there would also be massive costs in assets, and in the kind of major stink it would cause around the league. The Bruins would have a manageable $7 million cap hit for Trouba if they did indeed fire off seven year, $49 million offer sheet to the 6-foot-3, 210-pounder on Friday morning, and they would potentially fill in a big piece of their blue line puzzle for years to come.

But the Black and Gold would also surrender four first round picks given that they don’t have the draft picks to offer anything less than a contract with an AAV (Average Annual Value) of $9.3 million after shortsighted trades sent their 2017 second round pick (for Lee Stempniak) and 2017 third round pick (for Zac Rinaldo) to other teams. Wrinkles within the offer sheet language in the CBA would turn a seven year, $49 million contract into a $9.8 AAV for draft pick compensation purposes, but that doesn’t make it any easier for the Black and Gold.

Perhaps the one thing Bruins GM Don Sweeney didn’t anticipate, however, is the bad blood that poaching an RFA would create across a league where all 30 GMs apparently play by the unwritten NHL Commandment that “thou dost not offer sheet to anybody.”

If the Bruins indeed followed through with the massive offer sheet for a player that finished with six goals and 21 points last season, then the Bruins would live in fear that it could be open season on their own restricted free agents for the foreseeable future. There’s little doubt Winnipeg, and perhaps others, would come sniffing around 20-year-old right wing David Pastrnak when his contract is up next summer, and so on down the line with Boston’s next wave of talented young players coming through the pipeline.

There’s also the simple fact that opinions are very mixed on the ultimate NHL ceiling for Trouba given the possible investment involved. One Western Conference scout thought he was on track to become a No. 1 defenseman, and could be worth all of the assets involved in preparing an offer for a player like Trouba.

“He has elite skating, and has the shot to go with it. He’s built for the new age of mobile defenders that dominate through the neutral zone,” said the scout. “[The physicality] is there, but guys don’t punish anymore because you can push and pin. They defend with their sticks and feet. Upon zone entry is when they lay the body, and he checks all those boxes.”

One other NHL executive wasn’t so sure, and harbored some doubts about whether Trouba could be “The Man” for a blueline crew that had Stanley Cup aspirations.

“The physical tools alone allow him to be big minute guy, but his overall hockey sense could prevent him from being a top D-man,” said the exec.

That seems to be the knock on Trouba: he turns the puck over under pressure, and his decision-making while moving the puck hasn’t really improved from a rookie year as a 19-year-old where he posted 10 goals and 29 points. But the tools, the impressive body of work since entering the NHL as a teenager and the cachet of being a lottery pick keep all NHL observers ever-optimistic that a young player like Trouba will eventually figure it out.

There’s also the very real scenario that the Bruins don’t have the trade assets to get a young defenseman like Trouba given that the Edmonton Oilers had to surrender Taylor Hall in a one-for-one deal to get Adam Larsson from the New Jersey Devils. They have to hope they can build up some kind of trade package that could net them Kevin Shattenkirk or Cam Fowler, or hope that Jason Demers somehow picks Boston as his free agent destination.

That’s barring the offer sheet from the Bruins for Trouba, which is still being discussed by the Bruins even as it becomes less of a possibility for Don Sweeney heading into the July 1 opening of the free agent market. That’s because throwing an offer sheet at Trouba might be the only way the Bruins can land a young, potential No. 1 defenseman this summer that can give them the building block to compete for the next decade, and that’s something for Sweeney, Neely and everybody else on Causeway Street to seriously debate over the next two days.