The NHL is about levels, but it is about windows, too. Windows that are closing. Except the window that was supposed to be closed last year opened for the Capitals before Barry Trotz made like Johnny Keane and walked out the door with the championship belt wrapped around his waist.

Keane faded into ignominy in The Bronx; Trotz’ future will be determined while he straddles Brooklyn and Long Island.

The window has been opened for a long, long time in San Jose. Also Tampa Bay, where what has probably been the NHL’s best collection of talent the last three or four years has fallen short. The Predators have been long poised to make the final leap. And Vegas, well, for just how long are they going to fall short in the end before changes in management must be made?

The league is top-heavy again, with powerhouses ruling the Atlantic and Central divisions, once more setting up the likelihood of a playoff tournament short in integrity, featuring each conference’s best two teams in the second round. Postseason advantage, then, to the best teams in the other two divisions, of which the Caps and Golden Knights took full benefit last spring.

The power rankings

1. Tampa Bay

Steve Yzerman, likely waiting out the year until he takes command of the Red Wings, is gone, and it is doubtful that new GM Julien BriseBois will be able to wield the same hammer moving forward as did No. 19 in contract negotiations and trade talks. Mikhail Sergachev is an emerging nation on D who may force Ryan McDonagh to move to the right side.

2. Winnipeg

Patrik Laine may be the most natural goal-scorer in the league while operating for a club that has taken advantage of market patience — the good folks in Manitoba waited 15 years to get back their team, after all — to build painstakingly. But probably the last go-round for this group before cap realities force a break-up.

3. Nashville

Ryan Johansen has been somewhat less, hasn’t he, since coming to Nashville, where the six-deep defense has been at the core of Peter Laviolette’s success. (Note to Hank Lundqvist and the Rangers: Do not blame me if Johansen goes off for a hat trick and six points in Thursday’s opener.)

4. Boston

The Bruins are less spectacular than solid straight down the line and have managed to maintain assets necessary to get the deadline fix that, once concussed, Rick Nash was unable to supply last time around. They will be in on Artemi Panarin. Question is whether the B’s will be in on Sergei Bobrovsky, too, if Tuukka Rask is wobbly.

5. San Jose

How many points in the standings will Erik Karlsson be worth while fitting into a defense that has a 2003 Devils aura to it? The question, by the way, is rhetorical and not meant to be answered with a slew of indecipherable graphs.

6. Vegas

There is a foundation and presumably the same energy and relentless pursuit of the puck. Question isn’t whether the Golden Knights were a mirage, because they weren’t, but whether Marc-Andre Fleury can do it all over again.

7. Washington

Hey, Mr. (Tom) Wilson, will you ever learn and will your team and the league stop enabling your boorish and menacing behavior? Otherwise, no circumvention on Brooks Orpik (just as no circumvention on Detroit’s Henrik Zetterberg) because there is a clause in the CBA you may have overlooked denoting that circumvention cases only apply to the Devils and Ilya Kovalchuk.

8. Toronto

Wait; I thought that the Leafs weren’t going to have a care in the world relating to second contracts for William Nylander, Mitch Marner and Auston Matthews. Group that now includes John Tavares will be murderous on matches, and the power play should be an example of overabundance, but the question is whether Year 4 of Mike Babcock represents Year 1 of the team getting tired of hearing his voice?

9. Pittsburgh

A summer of rest for Sidney Crosby and Evgeni Malkin plus an expected rebound from Matt Murray in nets should separate these guys from a collection of deeper squads. But Jack Johnson? For five years? And if things should get a little dicey, it probably will not end so well for Phil Kessel.

10. Florida

Now imagine if the Panthers get Artemi Panarin from Columbus to add to their impressive stable of young talent. Word to the wise (plus anyone else still with me): Defend yourself next time, Mr. Ekblad.

11. St. Louis

Ryan O’Reilly gets his chance to prove the value that has been assigned to him throughout a nine-year career in which he has played a total of 13 playoff games.

12. Minnesota

It’s always been the wrong division for the Wild, hasn’t it, locked in with the Blackhawks in their glory days and now forced to contend with the Predators and Jets. Might have been a final four team — or finalist — out of the East but have won only two playoff rounds since investing $196 million signing Zach Parise and Ryan Suter to twin 13-year deals in 2012.

13. Los Angeles

Wrong conference for the Over the Hill Gang, even with marquee talents up front, on D and in nets. Ilya Kovalchuk should have come to Broadway.

14. Philadelphia

Assuming — always dangerous when it comes to the Flyers and goaltenders — Carter Hart proves the real deal in the AHL and displaces Brian Elliott/Michal Neuvirth before winter’s first snowball is thrown at Carson Wentz.

15. Dallas

Miro Heiskanen could be the game-changer for a team that has been less than the sum of its parts for a while. One playoff-round victory over the last 10 years represents the culture that Jim Montgomery is trying to cure.

16. Devils

Had Erik Karlsson landed in New Jersey, this would be one dangerous bunch. But the defection of John Moore diminished an already questionable blue line, and Cory Schneider is wearing a question mark on the back of his sweater. Even if Taylor Hall does it again — and he is capable — it will be more difficult for his team to repeat a playoff push.

17. Columbus

Game-breaking forward and No. 1 goalie each on final year of respective contracts prior to free agency, and neither is inclined to sign a new one even as the Jackets’ ownership/front office would essentially empty the vault for each. Not sure how any coach would do with that as the season evolves, let alone the one behind that bench.

18. Anaheim

Ryan Getzlaf hurt last year, Corey Perry hurt this year. Goalie John Gibson is one of the best in the league, but here’s a case of a window closing with management apparently not recognizing it.

19. Calgary

James Neal adds some production but the Flames are going to miss Dougie Hamilton on the ice even if not on their team field trips.

20. Carolina

The Candy Canes couldn’t even get their third jersey right, so they’ve added a fourth, suspiciously like the Hartford Whalers’ sweater. Wait, it is the Hartford Whalers sweater.

21. Colorado

Philipp Grubauer is the next in line to take over nets for an especially top-heavy Avalanche.

22. Arizona

The Coyotes thrived late last year after a dreadful start marked 2017-18 stillborn, so it remains to be seen what an emerging group can do when things are on the line. By the way, in the desert, it’s known as the Antti Raanta — not the Derek Stepan — deal, the affable goaltender having played so darn well.

23. Edmonton

Is it possible Cam Talbot is only the second-best backup the Rangers have traded this decade? If Connor McDavid cannot carry his team to playoff relevancy, then there will be ch-ch-changes (again) in the hierarchy.

24. Islanders

Lou Lamoriello is in command, which means the days of smoke, mirrors and gimmicks are over for this franchise. A methodical rebuild appears underway.

25. Rangers

Final projection is skewed because of the anticipated trade deadline shake-up that could come at the cost of a higher slot in the standings.

26. Chicago

The last time the Blackhawks were bad, the United Center was a ghost town. Pressure is immense on management of this team that is finally paying the fiddler.

27. Buffalo

The heavy lifting is primarily being left to the kids, who will rely on Rasmus Dahlin to deflect some of the pressure off Jack Eichel.

28. Montreal

Marc Bergevin apparently has decided to spend a bit more time explaining himself this season. Another example of a fellow learning how to say bonjour when he should be saying au revoir.

29. Vancouver

Trevor Linden was in for the long haul, foreseeing a Rangers-type operation. Ownership, not quite so much. So the Canucks signed Jay Beagle and Antoine Roussel to twin four-year, $12 million deals, which is something the Rangers might have done in 2009 or something.

30. Detroit

As Yzerman lays in wait, the Wings lay in state.

31. Ottawa

But don’t worry, owner Eugene Melnyk will find someone to blame. He usually seems to settle on the fans and/or the city.