Nashville Predators head coach Barry Trotz livened up an otherwise nondescript day for hockey news by dropping a little hockey analytics knowledge on beat writer Josh Cooper, defending the utility of defensive forward Paul Gaustad:
Predators coach Barry Trotz dropped in on the advanced stats debate when asked about the merits of center Paul Gaustad.
"His Corsi stat is probably not real great because he starts in our end the whole time," Trotz said. "But he's a real important part of our success."
In case that sounds like gibberish to you, the Corsi stat measures the balance of attempted shots by each team while a given player is on the ice. Trotz is defending Gaustad's poor results there (so far this season they're not bad, really) by pointing out that Gaustad starts many of his shifts by taking a faceoff in the defensive zone, and it is certainly true that when you get stuck back there more often than in the offensive end, it's going to hurt those numbers.
It's fun to finally see Trotz address this kind of stuff in public, because it's certainly true that the hockey operations department in Nashville has at the very least a passing interest in this stuff. I've had a few conversations with members of the team over the years on the subject, and they've previously engaged Eric Tulsky in a consulting role (by the way, check out his new blog Outnumbered here at SB Nation, it looks really promising).
This particular aspect which Trotz brings to mind today, that of the impact of Zone Starts on Corsi rates, was one I've looked at before with regard to the guy who formerly filled Gaustad's role on the Predators, checking center and faceoff specialist Jerred Smithson. Here's an excerpt from a guest blog I wrote for the Preds' website a couple years ago:
At first glance, Smithson's -10.8 Corsi doesn't appear impressive, since it means Nashville's opponents attempted about 10 more shots than the Preds for every 60 minutes of Smithson's 5-on-5 play. That was the lowest figure on the team last season among those who played at least 40 games.
We can set that performance in context, however, by looking at the conditions under which Smithson worked using another advanced stat, called Zone Starts. As one of the best faceoff men in the game (6th in the NHL at 57.4%), Smithson was typically sent out for defensive zone draws, so much so that over the course of the season, he was on the ice for 256 more defensive-zone faceoffs than ones in the offensive zone, the 3rd-greatest such imbalance in the league, behind Dallas Stars center Steve Ott and Vancouver's Manny Malhotra. Put simply, no matter how effective a player is, starting a shift in the defensive zone greatly increases the likelihood of giving up a few attempted shots by your opponent. The plan, then, is to minimize the damage and get play moving in the right direction as quickly as possible.
To extend our field position analogy, Smithson is Nashville's specialist at helping the team battle its way out of the defensive zone, and his basic Corsi Rating reflects the difficult circumstances he often faces. We can correct for that mathematically, however, and once those Zone Starts are factored in, Smithson's Corsi swings from a -10.8 up to +6.9, a stark difference that demonstrates his effectiveness at helping the team escape difficult situations on a regular basis.
Granted, as a coach I'd love to have such a player myself, who can perform so reliably in a role which takes on added importance late in games when you're trying to protect a lead. From my perspective, I can't see paying a guy in that role the kind of coin Gaustad is pulling down these days ($4 million this season, second-highest among Nashville forwards), but there you go.
As I've written before, these advanced stats aren't exactly rocket surgery, but they do provide a deeper level of understanding than you'd typically get from relying on phrases like "chemistry", "gel", or "jump". It's good to see this stuff get some validation from the Preds' head coach.