The Leafs and Expected Zone Shifts

The always enlightening and wonderfully-named Bettman's Nightmare posted a piece this morning at www.behindthenethockey.com about expected zone shifts.  I am not going to be able to explain this any better than him, so I'll just quote him at length:

Looking at Zone Starts more and more lately has brought me to the realization that I need something in the back of my mind to remember the expected finishes for players at each level of the spectrum.  To explain, Zone Starts (to horribly butcher and paraphrase these superior descriptions), a concept developed by Vic Ferrari, takes the number of faceoffs that start a player's shift and expresses it as a ratio of offensive zone faceoffs over the total of offensive and defensive zone faceoffs, or O-Zone FO / (O-Zone FO + D-Zone FO).  Paired with Zone Finish (which does the same equation with faceoffs that end a player's shift) and you have a loose idea of territorial control and coach usage, and the differential (coined "Zone Shift" by Ferrari) gives you a glimpse of whether the player is moving the puck in the right direction.  It's a pretty solid set of metrics, as high Zone Starts have had a positive correlation with Corsi, with the caveat that you need to have a sense of where the league-average Zone Shift is to know a.) players being deployed significantly in their own zone, and b.) whether the Zone Shift is below-average, roughly average, or above-average.  As Gabe's noted in the past, Zone Starts vis-a-vis Finishes pull hard to 50%, so anyone starting at 40% in the O-Zone is far more likely to finish with a positive Zone Shift, and anyone starting at 60% in the O-Zone is far more likely to finish with a negative Zone Shift.

As with most things, I immediately thought about how this applies to the Leafs.  Which Leafs outperform their expected zone shifts?  Which underperform?  The answers, after the jump, are not terribly surprising.

The chart below takes zone start and finish data from www.behindthenet.ca, adds expected zone shift (Exp. ZS from Bettman's Nightmare's piece linked above), and I have added two more columns: (1) "Zone Shift", which is just (ZS - ZF), and (2) Net Zone Shift (Zone Shift - Exp. ZS).  Bigger numbers are better and give an idea of how a player is performing compared to his peers around the league facing similar zone starts.

So what does this tell us?

• Mikhail Grabovski and Nikolai Kulemin are beasts.  Clarke MacArthur's numbers aren't quite as good which suggests that even though he leads the team in points he's perhaps being helped by his linemates more than he's helping them, possession-wise.  I'd love to see WOWY stats for these guys though since they play together so much there would be sample size issues.
• Colby Armstrong, Francois Beauchemin, Dion Phaneuf, Kris Versteeg and Darryl Boyce are all performing quite well, particularly since all five are in the Leafs' top 7 on quality of competition (as measured by Corsi Rel QoC).
• Carl Gunnarsson is once again, though much more quietly, having a very solid season, moving the puck in the right direction despite spending so much time saddled with Mike Komisarek and Brett Lebda.
• John Mitchell?  I have no explanation or comment.
• If Wilson is the stat cruncher he's made out to be we may have an explanation for why Luca Caputi, Korbinian Holzer and Christian Hanson saw so little time.  They got absolutely murdered in their cameos.
• Phil Kessel and Tyler Bozak are not strong possession players.  They have by far the worst numbers out of Leafs' "Top 9" regulars.
• Tomas Kaberle and Luke Schenn's numbers, while not terrible, are disappointing.
• Komisarek and Lebda are bad at hockey.
• Colton Orr is worse.

All in all, these numbers do not surprise me very much, which suggests they are a pretty good tool for evaluating players.

PS Thanks to Mirtle for sending me the chart sorted properly, and to Chemmy for mocking my Excel ineptitude.