It makes no sense for Lou Lamoriello to join the Islanders unless ownership gives the commander-in-chief command of the franchise. Any other concept or job description would be fatally flawed.

That means that Lamoriello, who is expected to talk with Scott Malkin/Jon Ledecky in the wake of being eased into a do-nothing senior adviser’s role in Toronto a few days after the Leafs’ first-round elimination, must be given complete control of the hockey operation — regardless of whether he assumes the title of general manager and handles the day-to-day duties generally associated with the position.

Lamoriello must set the agenda for the department and must have final say over personnel decisions.

It tends to be forgotten, but Lamoriello was hired as team president (only) by the Devils out of Providence College in May 1987 while Max McNab remained in place as general manager. After McNab procrastinated for weeks on a proposed deal with Vancouver in which New Jersey would have received Patrik Sundstrom in exchange for Kirk McLean and Greg Adams, Lamoriello named himself GM in September on the eve of training camp. He completed the trade within six hours.

Lamoriello would bring accountability to, and demand accountability from, an Islanders organization that has habitually trotted out rationalizations and excuses for repeated failures. Believe me, there have been enough of them provided for a team that has one playoff-round victory over the last quarter of a century. The attitude has been pervasive, too, even spreading behind the bench as often as not.

The clock, of course, is ticking on John Tavares’ potential free-agent defection. Maybe this whole thing with Lamoriello is a Hail Mary designed to keep No. 91 from walking through the door July 1. It had better be more than that. A year ago the narrative was that ownership had decided to keep Garth Snow as GM and Doug Weight as coach because Tavares was comfortable with them. Providing comfort has never been a priority for Lamoriello.

Adding Lamoriello to this organization cannot be a half-measure. Ownership must be committed to turning over the hockey operation in full to Lamoriello. Otherwise, there is no point to these discussions.

Stop me if you’ve heard this before, but B.U. coach David Quinn remains a viable candidate to take over the Rangers, who wrapped up their organizational meetings Friday. It is believed GM Jeff Gorton is waiting to talk to coaches who are currently working in the playoffs (NHL or AHL) before reaching a decision.

The only way I’m trading Kevin Hayes or Mika Zibanejad is if a legit top-four righty defenseman (now or future) comes back in the deal. The Blueshirts would love to be able to pry Jacob Trouba out of Winnipeg, but the impending arbitration-eligible Group II free agent is probably out of reach.

Calgary appears to have a surplus of right defensemen and could use help in the middle. Dougie Hamilton is the big name who might be obtainable, but I wonder if the Rangers might not target 20-year-old Adam Fox, who will be a junior at Harvard, in talks with the Flames.

Fox, Calgary’s third-round, 66th-overall selection in the 2016 draft, was Ryan Lindgren’s partner with Team USA in the past two World Junior Championship tournaments. The 20-year-old Lindgren, obtained from Boston as part of the pre-deadline exchange for Rick Nash, played 10 games with the AHL Wolf Pack after leaving Minnesota following his sophomore season.

Hayes, one of a select few Blueshirts who matched or exceeded expectations last year, is arbitration-eligible and one year away from unrestricted free agency. It may take five years at around $4.5 million per to get him under contract.

I doubt that Ryan Spooner fits into the Blueshirts’ long-term plan. The winger, reasonably productive but a bit too perimeter-oriented for a team that wants to transform into more of a straight-line attack mode, is also arbitration-eligible and a year away from free agency.

To that end, it may be difficult to move Spooner, who went 4-12-16 in 20 games after coming to New York as part of the Nash deal, at the draft. The Rangers will have to decide whether to sign the winger for one year — probably for around $3.5 million — so he can be available as a trade-deadline rental or simply allow him to become a free agent by not qualifying him.

With Lamoriello all but gone and assistant GM Mark Hunter probably going as well with the ascension of Kyle Dubas to GM, that seems to be it for the team of rivals assembled in Toronto by president Brendan Shanahan that includes coach Mike Babcock.

Dubas is wicked smart and the right man at the right time to take over the NHL’s most progressive operation. But the dynamic with Babcock — who has five years at over $6 million remaining on his contract, reports to Shanahan and had no trouble drawing boundary lines that he would not permit even Lamoriello to cross the last three years — will be fascinating to watch.

Fill in the blank: Derick Brassard was to the 2017-18 Penguins as (blank) was to the 2015-16 Rangers.

Yes, the answer is … Eric Staal.

For just as Staal was miscast as a third-line left winger, Brassard was miscast as a third-line grinding center for the two-time defending champion Penguins, who were outplayed and out-goaltended by the Caps in their second-round, six-game defeat.

I was surprised coach Mike Sullivan didn’t unite Sidney Crosby and Evgeni Malkin more often — they played together a total of only 1:16 over the final four matches after Malkin returned from an injury — in order to get Brassard more time on a more offense-oriented unit.

Brassard, who came to the Penguins from Ottawa at the deadline in a three-way deal with Vegas that cost the Penguins a first-rounder (plus), has one year remaining on his contract at just a $3 million cap hit and is likely to be on the move again this offseason.