Stuck in the Zone

Everyone has been talking about the Leafs in the defensive zone without a clue lately. It has been a very obvious thing about the team this year that they get stuck, cannot make clean exits, and when they do are often forced right back in the defensive zone again to start over.

This is not a post about how that's happening or my one neat trick for fixing it, but just the overview of what is actually happening without having to use the word "seems".

Note: this is an image-heavy post.

Edge

First up is NHL Edge zone time information. Produced via puck tracking, it is closer to a true time measure than shot-based approximations. Edge does not produce tabular data, so you only get the most basic idea of where the Leafs are relative to the league without any idea of the distribution of all the other teams. You can look at every team for each year if you like.

Normally, when looking at shot-based information, we split things in half, as if there are only two zones on the ice. This gives us no real understanding of what is a "good" amount of time to be in the neutral zone. Maybe less is better like Edge assumes, or maybe more means you're successfully transitioning before the other team even gains your blueline.

Given that, you need to look at the whole set of numbers to really get much from this. But one thing is very clear: The Leafs spend more time in the defensive zone than most other teams, and more time than they used to. But this is not a brand new issue.

The change in offensive zone time is also not a one-year phenomenon.

Shot-Based Metrics

Because Edge is shown at even-strength, I went with the same game state for the following look at shot metrics from Evolving Hockey. I picked Corsi to start because including all shots gives a result closer to the actual time in zone. If you start removing blocked shots, you've changed the meaning of what you're measuring.

In all of these, the Leafs are the blue line, and everyone else is the mass of grey just to give you an idea of where they sit. Note that almost all teams were duller in 2020-2021.

Once upon a time, we all acted like we thought Corsi Against was how you measured defending. Things are much, much more nuanced now. By using Expected Goals, two things happen: blocked shots are excluded, which is not necessarily good but is part of the reason why the lines will look very different, and the shots are weighted for quality by various measures.

I found the Expected Goals Against really, really interesting. The Leafs are not significantly different in outcome by this measure to how they were playing in the years with the most high-octane offence. So much for that see-saw theory about how you have to give up offence to have good defence.

I find it very difficult not to simply say the offensive system was bad this year. I don't believe in the see-saw, but I also don't believe these things are unconnected, so I think my first reaction is too simplistic. There is a relationship between time spent in the defensive zone and the amount of time you have left to be anywhere else. That's obvious since there's a clock on the game.

The two most alarming things are the shots against or the defensive zone time measure from Edge and the quality of the offence. And these feel like the most disconnected things shown, and yet I think we can picture the result of increased defensive zone time being wasted offensive shifts where there's a dump in and a line change. But that can't be the only drag on the pace and quality of offence.

But from things we've looked at earlier in the season, we have to remember that a lot of offensive zone time came from the depth, and a lot of the higher event periods in both ends came from the top six.

I don't think these lines are arrows pointing directly at the coach or the systems. I think there's player selection, player performance and also all the things those other teams do now they might not have been doing in 2016. Look at the background of the Corsi For chart to see that change rather dramatically revealed. It's harder today to keep the shots against down than it used to be.

I do think there's a very hard question to ask about the offensive system. What is it supposed to accomplish, and does it deliver? If the answer is fewer shots against, it's a massive failure. If there's some way that limiting offensive activity frees up players to defend more then maybe we can see that here, but was the gain worth the cost? But are the forwards actually hanging back more? And more than what?

Sheldon Keefe tried to solve the Leafs problem of rush chances against by holding the centre high in the offensive zone. John Tavares became useless and Auston Matthews spent a lot of time out where Mitch Marner roams. He happened to score a lot from those places, but it's hard to believe that was cause and effect and not a side effect of a great shooting year. The defensive zone time shot up not down.

Are there any meaningful clues in the playoffs where forechecking struggled to succeed? For some people the playoffs are everything, and the small amount of games, ones people actually watch, are great fodder for deciding how things seem. But is a few games against the same team really the one thing you should use to figure out where to improve your own?

Maybe the main issue is zone exits. But I think there's something wrong offensively, something that has been going wrong for a while. Some people like to say it's lack of speed, but I fairly stubbornly stick to my belief that fast players look exciting but their increased value is unproven.

Maybe this is the clue: In a world where the five-forward power play is gaining ground, the Leafs have to use two defenders on power play two because they don't have enough forwards up to the task most of the time. Maybe that's the first place to look for what's going on.