Bruins’ dominance is something to behold

How have the Boston Bruins been so dominant this season?

It’s becoming a more pertinent question as the regular season unfolds. It’s not that the Bruins don’t have significant competition, even within their own conference – teams like the Carolina Hurricanes, Toronto Maple Leafs, and New Jersey Devils have all shown themselves capable in the East. Out West, the Dallas Stars and Vegas Golden Knights have been similarly successful. Counting out the Colorado Avalanche – who have managed themselves through an injury-riddled first half – would also be a foolish bet.

But Boston’s dominance has been something to behold. They are 56 goals better than the opposition, which is nearly double that of second-place Dallas (+30). They have yet to incur a regulation loss on home ice (18-0-3). And with so many points in the bank, Jim Montgomery’s team only needs to play at a 62-point pace the rest of the way to qualify for the playoffs. A 62-point pace, I remind you, would normally be good enough for dead last in the NHL standings.

So, where has Boston built up such a competitive advantage relative to their peers? Much of it boils down to two themes. The first is the team is deep – perhaps they are due an upgrade on their fourth line come the trade deadline, but nearly every line and pairing combination Montgomery has put together has outscored the competition so far this season. The second is that this team remains impossible to crack defensively, and much of it has to do with the goaltending.

Whenever a goaltending tandem is stopping just under 93 per cent of shots faced, you can reasonably assume the netminders are playing a sizable role in their team’s success. And that’s what we’ve seen from Linus Ullmark and Jeremy Swayman through the first half of the season. But in the case of Boston, the play of Ullmark and Swayman has been additive.

If we control for the impact of goaltending by plotting real goals scored against expected goals against (a measure blind to goaltending performance and volatility), Boston still looks to be the most dominant team in the league. That’s because their offence is hard to slow down, and their defence even harder to crack: 

At the end of the day, we only care about actual goals. But expected goal scoring can be illuminating when evaluating a team’s play, particularly in a low-scoring league like the NHL. In the case of the Bruins, we see a dominant two-way skating team irrespective of how well the goaltending has played.

What does this look like in practice? Before Ullmark and Swayman even enter the equation, it’s nearly impossible to get inside into those premium scoring areas against the Bruins:

The other thing I would point out is this is also true at the skater level. If we look at every Bruins player year-to-date by real goals scored (on ice) and expected goals conceded (on ice), you see staggeringly favourable differentials. This looks like a team capable of dressing at least three quality lines and three defensive pairings – you probably can nitpick at the performance of a few depth players, but that’s about it:

Just about every single Bruins skater is in the positive this season whether you control for the goaltending or not, the only exceptions being depth forwards in Tomas Nosek and A.J. Greer. Any notion that the Bruins’ veteran roster is putting together a memorable finale season is bunk – those veterans are producing, but so too is the rest of the roster.

That brings me to the goaltending. I said it was additive, and the above table emphasizes just how much. If we look at goals saved versus expectations, we can measure goaltenders by controlling for the defensive play in front of them. We know Boston is a tough defensive nut to crack, and it’s why their team save percentages have been elevated for years. But compare what the team is yielding from Ullmark and Swayman relative to Bruins goalies of years past. They are getting the team out of jams when they need to:

Contrary to popular belief, the Bruins haven’t always had great goaltending. You can look as recently as last year, where a similarly dominant defensive team in Boston saw weaker than expected goaltending. Swayman and Ullmark last season gave up eight goals more than expected based on the profile of shots faced, and even behind a well-structured team, the Bruins finished 10^th in all situations save percentage.

This season? Different story. Boston’s combination of goalies have erased a staggering 20 goals – nearly four wins in the standings – from the ledger, most of that from the play of Ullmark. I’d be curious to know how much of Ullmark’s play has forced Montgomery’s hand a bit, too. This group was ripe for platoon work, where teams trade one elite goaltender for two quality ones that alternate starts. I think that was the plan to some degree in Boston, but Ullmark has been simply too good, and the Bruins have tilted usage in his direction.

All of this to say that it’s very hard to see what’s going to slow this Boston team down anytime soon. There is a goaltending regression coming, yes. And they are still dressing one of the oldest teams in the league, which lends itself to risks like heightened fatigue and higher injury risks.

But by and large they are blowing teams off the ice. And this story is one as old as time, at least in the modern era: build a dominant even-strength team with quality goaltending and you are nearly an impossible out when it matters most.

That’s easier said than done, but the Bruins have everything working right now.  

Data via Natural Stat Trick, NHL.com, Evolving Hockey, Hockey Reference