Re-Defining Defense

According to an old story, a lord of ancient China once asked his physician, a member of a family of healers, which of them was the most skilled in the art. The physician, whose reputation was such that his name became synonymous with medical science in China, replied, “My eldest brother sees the spirit of sickness and removes it before it takes shape, so his name does not get out of the house. My elder brother cures sickness when it is still extremely minute, so his name does not get out of the neighborhood. As for me, I puncture veins, prescribe potions, and massage skin, so from time to time my name gets out and is heard among the lords.” (‘The Art of War’, Thomas Cleary, 2005, p. 5)

In baseball, measuring defensive play has moved towards the ideal set by this parable. Eye-based evaluations unfairly credited a defensive player for making a routine play look outstanding, giving less credit to the player who makes it routinely, paralleling the eldest brother in the Taoist parable. This unfairly detracts from the player who prepares himself better prior to moment of fielding the ball.

In hockey though, the player who prevents the chance on their net that they had a hand in abetting is still generally looked upon favorably.

To be less abstract, Kevin Klein is that player.

If you ask an average Ranger fan, Kevin Klein is a steady defenseman that won’t hurt you in any way and who solidified the third pairing on his arrival. That third pair was in its defensive zone a lot more once Klein arrived, however. Using corsi-for percentage, which measures all shots attempts, John Moore saw less than 50% of all shot attempts go towards the opposition’s goalie compared to his own with Klein by his side. That’s a sharp decline from what he saw with Del Zotto.

If you’re thinking the difference might be that the Moore-Klein pairing was relied upon for more defensive heavy lifting than the Moore-Del Zotto pairing was: it isn’t so. John Moore’s usage didn’t change much at all after Del Zotto was swapped for Klein.

The third pairings, in both its Del Zotto and the Klein forms, started a lot more of their shifts in the offensive zone than the defensive one. Only in the Del Zotto form did it manage to play the majority of the time in the offensive zone, though.

Of course, it’s unfair to crucify Klein based on half a season of data. It turns out that half season reflects the rule and not an exception. In the four seasons from 2009-10 to 2012-13, Klein had played more than 100 5-on-5 minutes with 12 different defense partners. Of that sample, 10 of them had worse corsi-for% with Klein than without (even after eliminating time spent with Suter or Weber). Altogether the group averaged a 3.2% drop in shot attempts for vs. against when paired with Klein (weighted on ice time):

So it appears Klein more closely resembles the doctor who punctures veins and prescribes potions than the one who prevents sickness before it takes shape. Fortunately for our subject, defensive play is still largely defined by how a player looks in the defensive zone with no consideration of their role in being in the defensive zone in the first place.

If the Rangers plan on Kevin Klein taking the spot of Anton Stralman, whose case study reads the opposite of the Klein, they shouldn’t be surprised if they find themselves spending a lot more time in their own zone.

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