In the history of the NHL modern era that starts with the 1943-44 introduction of the red line, one coach and one coach only has won the Stanley Cup for the first time in later than his fifth full season behind his team’s bench.

That would be Al Arbour, who in 1980 won the first of his four straight with the Islanders in his seventh season in the wake of the history-making acquisition of Butch Goring to join Mike Bossy, Bryan Trottier, Denis Potvin and the rest of the dynasty.

This is Alain Vigneault’s fifth full season behind the bench on Broadway. It is safe to say that the Rangers coach is not necessarily safe for a sixth season, even if he has two years remaining at just over $4 million per on the contract extension he was granted in January 2017.

Management or ownership would be derelict not to review the situation following the end of this season that continued with Wednesday’s 6-1 Garden rout by the Bruins that marked the depleted, demoralized team’s fourth straight loss and seventh in the past eight games, all in regulation. That wouldn’t necessarily be unique to this year, but the severe breakdowns that have marked this step-back season will most certainly heighten the inspection of every part of the operation.

Know this. The Rangers would prefer not to make a change. There is much internal respect for Vigneault, who has earned it by coaching the team to the NHL’s sixth-best regular-season record over the first four years of his tenure while winning what is tied for the second-most playoff series victories over that same span.

But there are questions about longer-term viability of retaining a coach who has not yet won it all, and they are amplified when a team backslides. There are questions about an expiration date that are in fact asked all over the league in which 10 teams in the last 27 playoffs have won the Cup with a coach in his first season behind the champ’s bench, with five more winning in Year 2.

Truth be told, even with a lineup marked with deep potholes down the middle and on the blue line, which lately has been ravaged by injuries, the Rangers have not seemed responsive for long stretches at a time to Vigneault’s particular style, which might work best with a veteran team dotted with strong leaders.

The coach is a devout believer in allowing the players to establish the tone and in delegating off-ice authority to the men in uniform.

That’s a fine approach if there’s a fiery Cup-winning leader such as a Marty St. Louis or a pack of strong voices in the room, but there is ample reason to question whether that would be the most productive philosophy for a club that is expected to be unusually young next season.

There is also reason to question whether Vigneault is the right man to trust with the development of a very young team, given his tendencies to practice tough love on kids while according the benefit of the doubt to veterans, even those who are marginal NHLers. This is not at all unique among NHL coaches, but it does seem particularly pronounced here.

The Rangers’ play in the defensive zone has been chaotic for much of the past three seasons in concert with a deterioration of talent. But Vigneault has not seemed to adapt his on-ice system to his personnel. He wants to play the same way with this group as he did when a rising Ryan McDonagh, a younger Dan Girardi, a younger Marc Staal, a formidable Anton Stralman and a stout Kevin Klein were on the blue line. The front of Henrik Lundqvist’s net is the soft underbelly of the team that has gone unaddressed for years. The overload system meant to produce quick breakout passes seems too much for these past few groups to master.

Plus, there must be an inspection of whether Vigneault’s undying belief in whistle-to-whistle, turn-the-other-cheek hockey has created a passive mentality among the Rangers. When Chris Kreider stood up for McDonagh after the captain was run from behind by Steven Stamkos in Tampa Bay in Game 6 of the 2015 conference finals, No. 20 was rebuked by the coach for picking up an additional two minutes. When Brendan Smith stood up for Tony DeAngelo in an imbroglio in L.A. with Trevor Lewis on Jan. 21, he was chastised for picking up a bad penalty.

Again. Management and ownership are going to have to weigh the positives against the negatives, and they are going to have to weigh this known winning commodity against a yet-unknown available field. They are going to have to decide whether, after five seasons, Vigneault’s temperament is best suited to lead the next generation into the next era or whether he has taken the Rangers as far as he can.