Tracking Defensive Zone Entries: Andrej the Grey

This is the second post in a series tracking Oilers zone transitions. The first is here, introducing the project and explaining Zone Exits. This post introduces Defensive Zone Entries.

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An Ounce of Prevention

If we accept that the Oilers spend altogether too much time in their own zone (they do), then getting the puck out under control is only half the battle. The other half is not letting the other guys in the zone in the first place.

So in addition to tracking how the Oilers exit the zone, I’m also tracking how the opposing team enters the zone. As explored in Zone Exits, it’s insufficient to simply look at the number of times the puck goes in the zone. It’s how the puck gets there that is relevant.

Just as there’s Controlled Zone Exits, there’s Controlled Zone Entries. Many have written about the benefits of entering the zone with control of the puck as opposed to dumping it in, but I go back to Jen Lute Costella and her wonderful primer on zone entries. For the 5 of you who are reading this but haven’t read her yet… do so!

The take home is this: Teams that let the opposition to carry the puck into their zone give up more shots than teams that force the opposition to dump it in… and it’s not close. This makes sense. If the other team can carry the puck in, they maintain possession, they’re more likely to get a shot off, and get more scoring chances. If they dump it in, the first thing they have to do is get the puck back. It’s much less likely to lead to a shot.

So if we’re analyzing Oilers defensemen, it’s relevant to know if some defensemen are better at preventing controlled zone entries than others.

Defensive Zone Entries

This is not as straight-forward to track as zone exits. There’s a lot more judgement at play. What happens if the other team dumps the puck in for a line change? That shouldn’t really count. What about if the other team doesn’t even try to enter the zone with control, but crosses the red line and dumps it in (often off a neutral zone face-off, for instance). Should the defenseman on that side get credit when he did nothing to force the dump in?

As I was weighing different methods of tracking this, someone (and my apologies as I’ve forgotten who) pointed me towards Charlie O’Connor at Broadstreet Hockey who has been tracking Flyers zone entry/exit data all year (sample here). I liked how he identified the times a defenseman was targeted by the opposing team in trying to enter the zone and used that as a launching point for my own project.

My Project

Over the last 5 games of Mar 16 – 24 (starting one game later than my Zone Exit data) I tracked how the Oilers defensemen defended against zone entry attempts by the opposition. Since my goal was to try to separate out the skills of the individual defenseman and not the Oilers overall play, I did not include all zone entries against. I only counted ones where a defenseman was targeted.

For example, if a forward happened to be the primary defender for the puck-carrier (say in a 3 on 3 rush), that’s not counted. If the other team crosses the red line and dumps the puck in for a line change, that isn’t counted. Likewise, if the other team crosses the red line and fires the puck in for a dump and chase, making no attempt to gain the blue line and there’s no defender close to him to impede his progress, that’s also not counted.

As you can guess, there’s some judgement involved here. If there’s any question in my mind as to whether the defenseman was targeted, I assume that he was and try to establish that standard for all defensemen equally. There is certainly subjectivity in this data and I try to be as consistent as possible in my definitions. However, I fully acknowledge that I can not remove all subjectivity as I track this.

What to Track?

Obviously, the best outcome for the Oilers would be to deny the zone entry altogether. I coded this whenever the opposing team had possession of the puck in the neutral zone and the defender caused them to either lose possession of the puck or regroup. I only code this if the puck is past the red line, but that may be an artificial distinction that I remove next season. Intercepted passes are coded here as long as there is a clear target on the opposing team that would likely have gotten possession if the defender didn’t step up. Forcing the other team off-side is also a denied zone entry.

If you can’t deny a zone entry, the next best option is to force a dump in. I count this whenever the opposing team gets the puck into the zone but can’t maintain possession.

Finally, there is carries against, which include any controlled zone entry. The other team gets the puck into the zone by either carrying or passing it in, maintaining possession of the puck the whole time.

The Raw Data

As I did last time, I’ll start with the raw data. Again, the raw data on its own is not particularly useful, so I’ll break it down in the charts that follow. (And yes, I need a better name than “forced dump”)

Simplified definitions (details were expanded on above)

• Times Targeted – Times defender was targeted on a zone entry
• Denied – The defender prevents the opposing team from entering the zone
• Carry – The opposing team brings the puck in maintaining possession
• Forced Dump-in – The opposing team gets the puck but loses possession and has to get it back

You can see that the denied zone entries are awfully small numbers. I suspect this has to do with my definition being a bit too stringent, particularly requiring the denial to be between the red line and Oilers blue line. After tracking a few games, I think that boundary is somewhat artificial. If the opposing team has the puck in the neutral zone, anything that removes possession from them should probably count. However, for consistency I will finish out the year like this and look at changing it for next season.

Percentages

Firstly, let’s break down those numbers as percentages to get a better idea of what happens every time an opposing player tries to get in the zone. This chart is sorted from lower to higher carry percentage. If the goal is to prevent controlled zone entries, then a lower carry percentage is better.

So here’s the first surprise (for me anyways)… Sekera shows extremely well by this measure. Despite not denying many zone entries, he does better than his teammates at forcing a dump in. Sekera has the lowest carry percentage of any Oilers defenseman by far.

Fayne and Reinhart are in the next group. Both of them are not only better than the trio of Nurse, Oesterle and Clendening, but their results are fairly consistent game to game. As I watch closely for this aspect of gameplay, I repeatedly notice smart plays at the blue line by both of these defenders.

Nurse and Oesterle are next and also represent the most variable duo game to game. Nurse has had good and terrible games with allowing controlled entries… perhaps a sign of his youth. The first four games I tracked had Oesterle looking fairly poorly, but he pulled himself up with a strong game against San Jose. With a larger sample size, we’ll have to where he ends up.

Clendening is getting walked at the defensive blue-line. Game to game he consistently allows more zone entries against than anyone else. It’s… not… good.

Competition

Now, let’s put these numbers into some context, like last time. I tracked what percentage of their own time on ice was spent against the top forward from the other team (Tarasenko, D. Sedin, Landeskog, Hanzal, and Thornton).

If these numbers look a bit different from the equivalent graph in the Zone Exits post, that’s because they are. Against the Sharks, Sekera and Fayne managed to play only 20% of their minutes against Thornton while Reinhart and Oesterle were over 40%. That pulled the defense group much closer together, with only Clendening being something of an outlier. As a result, it makes Clendening’s high carry percentage even worse… he’s the only one significantly sheltered from the other team’s top line. Sekera continues to look strong, taking on top opposition and forcing them to dump.

Time On Ice

Another way to look at this data is to factor in time on ice. It helps make sense of the percentages to see how often a defender is letting the opposition walk into the zone. This chart looks at how often each defenseman is targeted on a zone entry and how many controlled zone entries they allow per 60 minutes of ice-time. It’s sorted by Carries/60.

Andrej Sekera you Grey Wizard you! By a significant margin, Sekera allows fewer controlled zone entries into the Oilers zone than anyone else. Meanwhile, Clendening continues to struggle… badly. He allows three times as many controlled entries as Sekera! We also see that Nurse doesn’t look good by this measure creating a bit of separation between him and Oesterle. The problem is that the opposition targets a zone entry on Nurse more than any other defenseman.

I’ll need to dig in deeper to understand why that is. It’s not because of higher competition. Perhaps Nurse and Clendening are struggling to keep the puck in the offensive zone. It also could be the quality of the teammates they play with. Maybe it’s a quirk due to the small sample size. Regardless, with Nurse and Clendening on the ice, the opposition is walking into the zone at a much higher rate than any other pairing by a large margin.

A Caution

I’ve only tracked this for 5 games, so a single good or bad game than skew the results one way or another. Specifically, against the Sharks, Oesterle and Nurse did excellent work preventing zone entries, which improved their numbers significantly. Here’s the Carry Percentage Against for the defensemen with and without the San Jose game.

One good game by Oesterle moves him away from ‘Clendening territory’ and closer to ‘Reinhart / Fayne territory’. Nurse also improves 5% based on this one excellent game. So we’ll need more data to see where everyone averages out to given time.

The Take Homes

• Andrej “The Grey Wizard” Sekera prevents zone entries at a much higher rate than I ever would have given him credit for. There’s a reason why he plays top opposition for the Oilers and he does well at it. At least in the 5 games I tracked, he’s head and shoulders above his teammates.
• Fayne and Reinhart have not been in Sekera territory in the small sample of games I’ve measured, but they do show their strength in preventing zone entries. When combined with the Zone Exit data, Reinhart looks like a fairly balanced defenseman… preventing zone entries at Fayne levels but with the ability to move the puck.
• Nurse struggles to prevent zone entries at times, though not as poorly as Clendening. He gets targeted more than any other Oilers D-man and combining him with Clendening has not been a good option. Much like the Zone Exit data, Nurse has shown the most variability game-to-game compared to the other defensemen.
• Oesterle pulled his numbers up thanks to a good game against San Jose, but he hasn’t been holding the blue line as well as his partner, Reinhart. Perhaps that’s why that pairing looks particularly well together.
• Clendening has been consistently brutal in the games I’ve tracked at preventing zone entries. He’s getting walked at the line regularly. Combined with his lackluster puck-moving and the sheltered minutes, he has not played at the level of an NHL caliber defenseman by my tracking (goal against San Jose not-with-standing).

Next Steps

• I will finish out the year tracking data to increase sample size.
• I’ll then dig deeper into these numbers for each defenseman.
• I’ve started a tracking give-aways in the defensive zone in a couple different ways. Once I get a few games under my belt, I’ll share what I find.