Sometimes life doesn't go as anticipated. Neither does a hockey season. We're one month into the 2019-20 NHL season and already teams are in recalibration mode thanks to surprising starts -- both good and bad (ahem, San Jose).

For this week's ESPN NHL Power Rankings, we assessed how preseason expectations match the reality after the first month.

How we rank: The ESPN hockey editorial staff submits polls ranking teams 1-31, and those results are tabulated to the list featured here. Teams are rated through Tuesday night's games, taking into account overall record, recent success and other factors such as injuries. The previous ranking for each team is their spot in last week's edition.

1. Boston Bruins

Previous ranking: 1

What we thought in the preseason: With core players Brad Marchand, Tuukka Rask, David Krejci, Patrice Bergeron and Zdeno Chara all north of 30, did Boston miss its best chance at another championship with this group?

What we know now: Sike! The veteran leadership on this team is coming through and the Bruins look even more dominant than we could have imagined. The top line is sizzling and the goaltending workload split between Rask and Jaroslav Halak is paying dividends.

2. Washington Capitals

Previous ranking: 2

What we thought in the preseason: Nobody could party harder than the Caps did in 2018, but after a season to reset, Washington could be a dangerous Stanley Cup contender again.

What we know now: Nobody could party harder than the Caps, though the Nationals did come close. Oh, and the Caps look scary good, averaging nearly four goals per game.

3. New York Islanders

Previous ranking: 11

What we thought in the preseason: So they had one magical season where everything went right. Is the structure that strong that they could replicate it -- even with saying goodbye to Vezina Trophy finalist Robin Lehner?

What we know now: OK, so maybe Barry Trotz's system is that good (and the personnel is good enough too). The Isles are giving up the fewest goals in the league, and Semyon Varlamov slid in to Lehner's role in an effective time share with Thomas Greiss.

4. Nashville Predators

Previous ranking: 6

What we thought in the preseason: The Predators finally landed their coveted No. 2 center in Matt Duchene. The offense -- which became stagnant last season -- needed to improve.

What we know now: One month in, the Preds have the best offense in the NHL. They're averaging a league-high goals per game, and don't seem to have seller's remorse for trading away P.K. Subban to clear cap space.

5. St. Louis Blues

Previous ranking: 13

What we thought in the preseason: The trade for Justin Faulk right before the season signaled that GM Doug Armstrong didn't want to entertain any talk of a Cup hangover; the Blues were going all-in to try to go back-to-back.

What we know now: What's a Blues season without a little adversity? St. Louis is still collecting wins, despite the long-term absence of Vladimir Tarasenko. Now they need to prove it's sustainable.

6. Edmonton Oilers

Previous ranking: 9

What we thought in the preseason: Connor McDavid and Leon Draisaitl will shoulder the offensive burden, and drag this team as far as they can.

What we know now: OK, so it's still the McDavid and Draisaitl show. But at least they have a third sidekick now in James Neal (11 goals). The trio has accounted for 31 of the team's 45 goals, a whopping 69% of the offense.

7. Carolina Hurricanes

Previous ranking: 4

What we thought in the preseason: Saying goodbye to Faulk felt inevitable, because he was due for a big new contract and this team had a surplus of capable defensemen.

What we know now: The Canes still have too many blueliners, and might be in the market to trade one. What they'd want in return: a top-nine scorer. So, not much has changed.

8. Vegas Golden Knights

Previous ranking: 7

What we thought in the preseason: Now that they have Mark Stone and Max Pacioretty acclimated to the roster, the Golden Knights should surge as Western Conference favorites.

What we know now: The Golden Knights have been a little inconsistent, and don't have the typically strong possession numbers we usually see from them. Once again, they're relying heavily on Marc-Andre Fleury (he has started 13 of their 16 games).

9. Buffalo Sabres

Previous ranking: 5

What we thought in the preseason: This was going to be another forgettable season in Buffalo. As the team adjusted to yet another new coach, it's unlikely the Sabres could keep up with the talented Atlantic Division.

What we know now: So they've fallen back to earth after a torrid start (and need to find a way to generate more offense at even strength). But this team had sneaky good upgrades in the offseason, and could contend for a playoff spot.

10. Vancouver Canucks

Previous ranking: 12

What we thought in the preseason: Not much, really. The Canucks didn't do anything this offseason to warrant attention, and they were poised to be slightly better than last season's pedestrian squad.

What we know now: This offense is sizzling hot (five or more goals in five of their past seven games). Meanwhile, there's no sophomore slump for Elias Pettersson; with 20 points in 15 games, he's creeping into the Hart Trophy conversation.

11. Colorado Avalanche

Previous ranking: 3

What we thought in the preseason: Everyone's favorite Stanley Cup sleeper team is no longer in position to surprise people. Now the Avs have to live up to the hefty expectations.

What we know now: The Avs looked great until they lost two-thirds of their top line, Gabriel Landeskog and Mikko Rantanen, to injury. Luckily, GM Joe Sakic added depth forward help this offseason, which is helping keep this team afloat.

12. Toronto Maple Leafs

Previous ranking: 8

What we thought in the preseason: With over $33 million in cap space devoted to three forwards (John Tavares, Auston Matthews, Mitch Marner), this team is on the clock to win. The offense better produce, and anything short of a long playoff run is a disappointment.

What we know now: A sluggish start (by their standards) can be attributed in part to injuries. The offense is producing (ranking seventh in the NHL with 3.44 goals per game) but something still feels amiss.

13. Arizona Coyotes

Previous ranking: 16

What we thought in the preseason: The Yotes were decimated by injuries last season, but with everyone back -- especially goalie Antti Raanta -- they should be a playoff team.

What we know now: They've had slightly more luck on the injury front (though Niklas Hjalmarsson is out long term). Though it's nice having Raanta back, Darcy Kuemper has been the star in net (10 starts, seven wins, a league-best .940 save percentage and 1.69 goals-against average).

14. Pittsburgh Penguins

Previous ranking: 10

What we thought in the preseason: That we'd spend the entire season wondering whether shipping Phil Kessel out -- and bringing in Alex Galchenyuk, Dominik Kahun and Brandon Tanev -- would make the offense better or worse.

What we know now: It's hard to assess this team's capabilities considering the injuries that the Penguins have had to endure. Just when they got everybody back, Patric Hornqvist was sent to IR.

15. Tampa Bay Lightning

Previous ranking: 14

What we thought in the preseason: The juggernaut returns. This ultratalented and deep lineup will be able to rebound from the playoff collapse. After tying the NHL record with 62 wins last season, this is still the team to beat in the East.

What we know now: The Lightning are having a hard time shaking off being swept out of the first round last season. Sure, they're banged up, but one of the reasons they're not seeing success, as defenseman Ryan McDonagh told reporters last week, is that they're "lacking confidence."

16. Calgary Flames

Previous ranking: 17

What we thought in the preseason: The Flames should build off last season's success, but goaltending could be their demise. After all, would you trust a goalie tandem led by Cam Talbot?

What we know now: Forget Talbot, it has been David Rittich's show. Rittich, who reportedly curbed his Coca-Cola addiction in an offseason reset, has faced a league-high 461 shots and is shining, with a .915 save percentage.

17. Florida Panthers

Previous ranking: 18

What we thought in the preseason: Joel Quenneville and Sergei Bobrovsky are here to save the day. The two splash offseason acquisition should transform this perennially underrated team into a playoff contender.

What we know now: The Panthers have erased a brutal start and seem to be finding a rhythm under Quenneville, winning five of their last seven. Bobrovsky's early play (.882 save percentage) is concerning, but at least he got his first shutout this week.

18. Anaheim Ducks

Previous ranking: 15

What we thought in the preseason: The only good thing going for the Ducks this season is John Gibson, who is going to be burdened with a massive workload yet again. Maybe this is the year to throw in the towel on some of the veterans.

What we know now: The Ducks have relied on Gibson -- especially since the defense is depleted by injuries -- but the kids look all right, and have kept this team within playoff position. They're really bad at tanking.

19. Montreal Canadiens

Previous ranking: 19

What we thought in the preseason: The Canadiens are a bubble playoff team, and could make a run. But they need serious fixes to their power play, which was second worst in the league, at 12.9%.

What we know now: Montreal is still on the playoff bubble, and we're still cautiously optimistic about a run. But the serious fixes are now urgent for the penalty kill, second worst in the league, at 68.9%.

20. Winnipeg Jets

Previous ranking: 20

What we thought in the preseason: Things surely would quell after a dramatic summer, in which Patrik Laine and Kyle Connor both needed new contracts, and Dustin Byfuglien announced, on the eve of camp, he was taking time away from the team.

What we know now: Things have not calmed down. The Byfuglien situation is lingering, and potentially brewing into something more serious. If the NHLPA files a grievance against the team, the Jets could be in cap trouble yet again.

21. Philadelphia Flyers

Previous ranking: 22

What we thought in the preseason: The savior is here! Carter Hart, just 21, could offer the solution to a decades-long quest for quality goaltending in Philly.

What we know now: We're reminded that Hart is just 21, and is going to go through some growing pains (he has a .885 save percentage through nine games). For now, the Flyers are opting for a near-even split with veteran Brian Elliott.

22. Dallas Stars

Previous ranking: 24

What we thought in the preseason: With a stud goalie tandem and strong defensive structure, the Stars were poised to build off last season's success. They just need to amp up the offense a bit.

What we know now: The Stars started the season looking quite slow, and the offense was dreadful. They've picked things up recently but will face some adversity with John Klingberg out of the lineup for at least two weeks.

23. Columbus Blue Jackets

Previous ranking: 21

What we thought in the preseason: The Blue Jackets were going to go into us-against-the-world mode, and play with vengeance in spite of all the players who left. Also, the power play couldn't be worse than last season's, right?

What we know now: The Blue Jackets are motivated to win, but they just might not have the depth to do it as consistently. And the power play is just as bad as last season.

24. New Jersey Devils

Previous ranking: 30

What we thought in the preseason: With Jack Hughes, P.K. Subban and Wayne Simmonds coming into the fold, this team was surely headed back to the playoffs and tri-state area relevancy.

What we know now: After going winless in their first six games, we got nervous. But putting assistant GM Tom Fitzgerald behind the bench has been an effective wake-up call.

25. New York Rangers

Previous ranking: 25

What we thought in the preseason: The rebuild is over! The kids are here, and ready to save the day, bringing Henrik Lundqvist one last chance for Stanley Cup glory.

What we know now: The goal now is to see steady improvements from Kaapo Kakko, Filip Chytil, Lias Andersson, et al. In other words, the rebuild is almost over, but we're not quite there yet.

26. San Jose Sharks

Previous ranking: 23

What we thought in the preseason: Veteran squad, Stanley Cup aspirations; it should just be rinse, wash and repeat at this point, yes?

What we know now: Not quite. Perhaps we overestimated the goaltenders' competence, or underestimated the loss of Joe Pavelski and Joonas Donskoi. Or maybe the defense is just really taxed. Whatever it is, this Sharks team has been rotten.

27. Chicago Blackhawks

Previous ranking: 26

What we thought in the preseason: This is a confusing team, straddling two eras. The Blackhawks want to stay competitive without tearing it all down, but that's easier said than done.

What we know now: They have turned to the kids. The (potentially for the long term) arrivals of Kirby Dach and Adam Boqvist means Chicago knows it needs to start thinking about who will be franchise leaders years from now.

28. Minnesota Wild

Previous ranking: 28

What we thought in the preseason: Paul Fenton did his fair share of damage in his short time as GM, but there are still talented players on this roster (though some are old, with lengthy contracts).

What we know now: Things were a little worse than we predicted. Among the issues for new GM Bill Guerin: how to get the most out of inconsistent players such as Victor Rask and Kevin Fiala, and whether they should be traded.

29. Los Angeles Kings

Previous ranking: 29

What we thought in the preseason: Not much to look forward to in Los Angeles this season, until the Kings can start incorporating their prospects (and they do have an impressive prospect pipeline).

What we know now: It's going to get worse before it gets better. The goaltending is bad. The team gave up five goals in four straight games. Trade rumors swirl, but the fire sale of aging vets might just be a pipe dream.

30. Ottawa Senators

Previous ranking: 31

What we thought in the preseason: The least talented roster in the NHL was going to win very few games. The biggest goal? Avoiding more drama.

What we know now: Under first-year coach D.J. Smith, the culture is in better shape. The team has a few more wins than expected, but it's still a bleak outlook.

31. Detroit Red Wings

Previous ranking: 27

What we thought in the preseason: It's going to be a long and potentially ugly season as the rebuild trudges on, but the top line will be able to provide at least a few highlights.

What we know now: It's ugly. Detroit has a league-worst minus-29 goal differential. And the top line has been the only highlight: Dylan Larkin, Tyler Bertuzzi and Anthony Mantha have scored 19 of the team's 34 goals.