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The Sharks Got Scarier

Since the 2008-09 season, no NHL team had played with more than one former winner of the Norris Trophy, given to the league’s top defenseman, according to the Elias Sports Bureau.1 But all that changed last week when the San Jose Sharks shook the NHL by trading for Erik Karlsson, among the league’s most coveted defensemen.

Karlsson — a two-time Norris Trophy winner and the league’s highest scoring defenseman since the beginning of the 2009-10 season2 — will be joining a defensive core that already features Brent Burns, the uber-bearded, gap-toothed wonder who won the 2016-17 Norris Trophy while scoring 29 goals for San Jose. The move obviously makes the Sharks a better and more offensively dangerous team, but the extent to which it does so has the potential to be historic.

Last season’s numbers don’t paint a full picture. Both defensemen had relatively down years offensively: Burns and Karlsson each had their lowest goal totals since the 2012-13 season.3 Each player also experienced a dip in goals versus threshold (GVT):4 Burns posted his worst mark (13.0) since 2013-14, while Karlsson had his worst season (9.9) since 2012-13. But each player is still very much in the prime of his career: Burns is 33 years old, while Karlsson is just 28. And just look at what they did in the two seasons before last year.

During the 2016-17 season, Burns’s GVT was 24.1, while Karlsson’s was 19.7 — the highest two values among defensemen that season and some of the highest in the league since the lockout of 2004-05. The harmonic mean — a special kind of mean that balances between the two values being averaged, so as to capture true tandems (rather than one-man shows) — for the two was 21.7, which would place them among the greatest blueline duos in NHL history if they repeated it as teammates.5 In the previous season, they were collectively even better: Burns’s GVT was 23.5, Karlsson’s was 21.5, and their harmonic mean was 22.4

It’s unlikely that both Burns and Karlsson will play to those levels again in 2018-19, but if they were able to match their tallies from the either of the two preceding seasons, they would become one of the most prolific defense tandems by the harmonic mean of GVT in the NHL dating back to at least 1951.

Burns/Karlsson could claim a spot among the top D tandems

The top defensemen duos by the harmonic mean of their goals versus threshold*, 1951-2018, compared with the output of new San Jose Sharks teammates Brent Burns and Erik Karlsson in recent seasons

Top defensemen duos in NHL history
goals vs. threshold
Year Team Player duo individual Harmonic Mean
1976-77 MTL Larry Robinson 29.6 27.9
Guy Lapointe 26.3
1974-75 BOS Bobby Orr 46.2 25.4
Carol Vadnais 17.5
1970-71 BOS Bobby Orr 47.1 25.1
Dallas Smith 17.1
1974-75 MTL Guy Lapointe 23.8 23.1
Serge Savard 22.4
1993-94 NYR Brian Leetch 23.2 22.3
Sergei Zubov 21.5
1985-86 PHI Mark Howe 26.0 22.0
Brad McCrimmon 19.0
2007-08 DET Nicklas Lidstrom 25.0 22.0
Brian Rafalski 19.6
1975-76 NYI Denis Potvin 27.7 21.6
Jean Potvin 17.7
1973-74 BOS Bobby Orr 40.4 21.4
Carol Vadnais 14.6
1995-96 DET Nicklas Lidstrom 21.4 21.3
Paul Coffey 21.3
Burns and Karlsson over the past four seasons
Year team Player duo individual Harmonic Mean
2015-16 SJS Brent Burns 23.5 22.4
OTT Erik Karlsson 21.5
2016-17 SJS Brent Burns 24.1 21.7
OTT Erik Karlsson 19.7
2014-15 SJS Brent Burns 15.1 15.0
OTT Erik Karlsson 15.0
2017-18 SJS Brent Burns 13.0 11.2
OTT Erik Karlsson 9.9

*GVT is estimated for seasons since 2015-16.

Sources: Hockey Abstract,

Before the Karlsson acquisition, San Jose already got a lot of production from its blueliners: With Burns and Marc-Edouard Vlasic (a regular recipient of Norris Trophy votes), Shark defensemen scored 199 combined points last season, which ranked third in the NHL behind the Nashville Predators (206) and the Minnesota Wild (200). Adding Karlsson, who has averaged 0.83 points per game in his career, makes the Sharks the smart bet to lead the way in points from defensemen in 2018-19.

If the Sharks are able to eclipse 200 points from its defensemen, it too would be historic: Since the NHL lockout of 1994-95, just 21 teams have accomplished that feat.6 It happened just 14 times during the aughts and has been achieved just six times since the beginning of this decade.

The knock on Karlsson early in his career was that, while impressive in the offensive zone, he lacked something in the defensive zone. His zone starts tell a different story, however — in each of the past five seasons, more than 44 percent of the faceoffs for which Karlsson has been on the ice have taken place in his defensive zone, indicating a vote of confidence by the Ottawa Senators coaching staff in their best player’s defensive abilities.

The addition of Karlsson should also vastly improve San Jose’s power plays. Among the 11 teams that finished with 100 or more points during the 2017-18 season, the Sharks had the third-worst power-play percentage, scoring on just 20.6 percent of their chances. Of the 518 points Karlsson has scored in his career, 195 have come on the man advantage. Tacking on an additional 0.3 power-play points per game should vastly improve the prospects of a team that was perfectly mediocre with the man advantage in 2017-18.

A player of Karlsson’s ability would make any team in the NHL better. The Sharks hope that a player of Karlsson’s ability makes them so much better that they’re finally able to get over the hump as perennial would-have-beens to win their first Stanley Cup.

Neil Paine contributed research.


  1. In 2008-09, the Anaheim Ducks had former top defensemen Chris Pronger and Scott Niedermayer, while the Detroit Red Wings had Chris Chelios and Nicklas Lidstrom.

  2. Karlsson’s rookie season.

  3. A lockout shortened the 2012-13 season by 34 games.

  4. GVT was developed by Tom Awad of Hockey Prospectus and is similar to baseball’s Value Over Replacement Player (VORP), in that it seeks to determine a player’s value in goals above what a replacement player would contribute. In this analysis, we used the GVT values found at Hockey Abstract for seasons before 2016-17. For subsequent seasons, we estimated it for skaters using’s Point Shares as our underlying guide.

  5. Harmonic means capture duos with two exceptionally productive players. It would be easy enough just to add up the GVT values for each team’s top two defensemen, but that might capture cases in which a disproportionate amount of value was added by only one player. (The most extreme example might be on the 1970 Boston Bruins, whose top two D-men, Bobby Orr and Dallas Smith, produced a staggeringly high summed GVT of 47.0 … of which 41.2 belonged to Orr alone. That wasn’t so much a “tandem” as “Orr plus whoever happened to finish a distant second behind him,” which is what we want to avoid. Their harmonic mean, however, was much lower — 10.2

  6. It happened 148 times between the 1970-71 and 1993-94 seasons.

Terrence Doyle is a writer based in Boston, where he obsesses over pizza and hockey.