Defense is not a four-letter word, but when it’s bad, it extracts a select few.
During the off season, fresh off a calamitous first round exit after being up 3-1 in the opening round against the eventual Finalist, Montreal Canadiens, the Toronto Maple Leafs signed two players that should have a distinct defensive impact.
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David Kampf and Ondrej Kase both offer a structural defensive skillset. If there was one thing Toronto could have taken away from the first-round exit, it was the impact of Philip Danault, a defensive pivot that took his services to the Los Angeles Kings.
Defensive metrics, unlike offensive metrics, measure the lack of events, rather than the accumulation of events like goals, shots, shot attempts, and eventually assigning a numerical value to shot location to determine expected goals. There’s still a woeful lack of dependable defensive metrics in the public sphere that can isolate defensive effectiveness. An illustration is this tweet from Evolving Hockey.
The offensive metrics indicate just how effective Eriksson Ek was, with very few defensive events against to show showcase effectiveness. Now, Eriksson Ek is mature and structurally competent, but it wasn’t solely because he was on the ice that those defensive metrics were so good. There’s a team level effect that isn’t captured in isolation. Any teammate’s mistake, or out of position, or assumed risk will change the outcome of those events and mar what could have been perfect defensive play on the part of Eriksson Ek.
Individual impact is dependent on systems play, and the structure afforded to players that stay within that confine, or can flow within. Game flow is dependent on this type of structure. The lack of defensive metrics – that is, effective shot and scoring chance suppression – is a team wide effect, but we still try to measure individual effect like we measure offensive results. There are plenty of individual characteristics that define proper defensive play and video and skills development coaches can spot those while going through hours of video.
Kase and Kampf
Toronto’s strength relies on their skilled forward group and quick strike capability, but they missed a true defensive foil, like Danault. That need, in an economically viable capability fell upon their research and development teams as well as any advanced scouting and information via networks. They identified both players for their skillsets as candidates and signed both players.
Kampf was a less than heralded as a depth component on a lowly Chicago team, a bit more of a unknown commodity that came at a decent price for short term, while health is the biggest hurdle facing a productive season from the former Duck and Bruin, Kase.
The graphs below show the differentials between goals against and expected goals against and rebound goals differential. I chose to highlight rebounds because effective defensive play should all but eliminate rebound chances. Even for allowing low danger shots on goal, the follow up to ensuring there isn’t a secondary chance after the initial shot is paramount. Defensive structure should swallow up that puck and effectively begin the transition back to offense.
The data is courtesy of MoneyPuck.com which contains an extensive amount of different data points including rebounds, on and off ice stats, and danger area stats – broken down by low, medium and high danger areas, in addition to the regular suite of shot based and expected goals metrics. It’s an interesting breakdown in which I encourage curious parties to explore.
So, when the Toronto Maple Leafs signed David Kampf and Ondrej Kase, how did they actually decipher that these two players would be ideal fits to supplement their defensive play? We will explore that using the charts below, some from data from MoneyPuck, and isolation data accumulated and visualized via HockeyViz.com.
David Kampf
The chart below is a 10-game moving average in career differential for expected goals against and rebound goals. Ideally the blue dotted line should be below the zero (0) mark and aside from some occasional spikes above that mark, Kampf has been a steady defensive player while on the ice. Rebounds (the black dotted line), should follow the same pattern, with mostly situated below the zero mark. As events, expected goals against are numerous in comparison to rebounds, so the spikes in expected goals that match with spikes in rebounds are indications of less than stellar defensive play.
Recent play from the 2020-21 season really shows how instrumental Kampf’s defensive presence is to his team.
HockeyViz has isolation metrics for subscribers that attempt to attribute individual effect to on-ice events, and the results are plotted in a heat map in the defensive zone. Notice the negative expected goals (xG) values in the bottom half of the charts, with a lot of blue. Red impact means more against metrics, and the bluer the better.
Ondrej Kase
Using the same chart for Kase shows much more fluctuation in expected goals against, but that includes a lot of time on an unstable Anaheim Ducks team before moving to Boston where he didn’t see much action. The fragility of Kase is well documented and can become problematic if the expectation is to fill a desired role without a competent back up plan.
The most recent upswell in expected goals against (the blue dotted line) is the height of the Ducks on-ice woes, before moving to Boston where the trend declines back towards zero, and then his effect in Toronto at the very far end to the right of the chart.
Kase actually has had a lot of two success so far in Toronto blue and whites, and has been a solid factor offensively, as well, being on the ice for a high amount of high danger scoring chances. With the Leafs trying to balance their roster, this likely changes over time, but it’s encouraging to have defensively responsible players contributing the offense.
Similar to Kampf, Kase’s isolated impact defensively shows a lot blue in the defensive zone, with exceptional expected goals values. The bluer the better, until the Ducks reeling from ineffective play moved the winger to Boston.
There’s still a lot to evolve defensively and my personal feeling is that in conjunction with the available defensive metrics, skills and developmental coaches will have a direct impact on the current group of NHL players. If the measurements become more effective, the trickle down effect into superior defensive play will translate for players that can flow through transition.
Defense should not be solely defined as ‘shot suppression’. The transition and retrieving pucks is another true measure of defensive effectiveness, that is currently unavailable in the public sphere.
But, a guy can dream.
