Is a Robyn Regehr-Andrej Sekera Pairing a Good Idea?

A good example of the dangers and proper application of WOWYs.

Now that the Kings have acquired an exciting new player, it's time to figure out where he fits in the lineup. Sekera is a left shot who can play the right side, and all indications are he'll be asked to do that in LA. Dean Lombardi hinted at trying Sekera with Regehr, so I'm guessing the Kings will soon roll out a combination like this:




Once Martinez returns from injury, he will probably be swapped in for McNabb. The big advantage of this setup is that it gives the Kings two tried-and-true pairings, Muzzin-Doughty and Martinez-Greene. All four of those defensemen are excellent play drivers, Muzzin and Doughty so much so that they have a good case for best pairing in the NHL. Martinez-Greene is way above average for a third pairing, too.

But is SekeRegher really a good idea? The pairing has some logic to it, being one of those puckmover/puckstopper combos that the Kings love. But those two last played together on the 2013 Sabres, and the results were gnarly. Check out the WOWY (Regehr's "without Sekera" numbers adjusted to only include his time in Buffalo):

Regehr-Sekera, 2013

Corsi% TOI
Sekera with Regehr 36.5% 191
Sekera without Regehr 46.5% 434
Regehr without Sekera 42.0% 163

Yikes. You never want to see Corsis in the mid-30s. It's not quite as bad as it looks because the 2013 Sabres were really bad (45.1% Corsi) and Sekera-Regehr were getting somewhat tougher zone starts than the rest of the team. Still, though, that's a terrible performance. We'd expect Regehr to lower Sekera's Corsi% because, well, he does that to everybody. But it's strange that Regehr had more success with other defensemen in Buffalo, like Tyler Myers, than he did with Sekera - even though those other players are not as good as Sekera. Do Regehr-Sekera have some sort of anti-chemistry, making the whole less than the sum of its parts?

Fortunately, I think the answer is probably no. WOWYs cannot be used to establish that two players have chemistry, or a lack of it, which makes them especially good or bad together beyond what their individual talents would suggest. CanesAndBluesFan at St. Louis Game Time published an excellent series of posts on this. The point is that WOWYs are highly prone to randomness. Take enough combinations of two players and some will appear, purely by chance, to have a dramatic effect. Some will even appear "statistically significant" while being nothing more than the product of randomness. Of course, the occasional WOWY might be in truth the result of chemistry, but the odds will always be that it's nothing but statistical noise.

WOWYs must instead be carefully applied over samples as large as possible. If a player makes everyone he plays with much better or much worse year after year, that is very important and useful information. But trying to do more than that with WOWYs is probably a mistake.

It shouldn't be a surprise that if we look at the larger sample of 2011-12, the results become more normal:

Regehr-Sekera, 2011-12

Corsi% TOI
Sekera with Regehr 46.0% 368
Sekera without Regehr 52.8% 741
Regehr without Sekera 44.5% 787

That's a more reasonable pattern. Sekera is worse with than Regehr than without, but that's no surprise, as Regehr has always destroyed the Corsi% of his defense partners. But Regehr also does better with Sekera than without, which makes sense because Sekera was one of the strongest defenseman on that Buffalo team. The awful 36.5% of 2013 was probably a fluke.

So the Kings can pair Sekera and Regehr, which will free up other defensemen to form excellent first and third pairings. Since Sekera and Regehr's recent results together can safely be ignored, the Kings can expect much better results from this pairing than they would have gotten from, say, Regehr-McBain. The trade is a big boost to the defense.

Of course, since Regehr has a long track record of making everyone he plays with worse, it's worth asking why have him on the second pairing at all, instead of a guy like Brayden McNabb, who appears to be fairly neutral as a possession player. There is of course no good reason, other than that is not the world we live in. The Kings have given every indication they are going to play Regehr the rest of the year. The arrival of a puck-moving, play-driving partner like Sekera will help make the best of that unfortunate situation.