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Data Analysis: What Does the Ryan Ellis Injury Mean for the Predators?

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An in-depth analysis on the Ellis injury from our newest contributor, Adam Jazdzewski.

2017 NHL Stanley Cup Final - Game Six Photo by Bruce Bennett/Getty Images

Ryan Ellis was a warrior in the playoffs for the Nashville; he finished the Predators incredible run with five goals and eight assists for a total of 13 points in 22 playoff games. His point production tied him with forwards Victor Arvidsson and Ryan Johansen for 3rd on the team, just three points behind team leading Filip Forsberg’s 16 and one behind Roman Josi’s 14. The Stanley Cup run the Predators went on shifted Ryan Ellis from relative obscurity outside of Nashville and into the international spotlight, showcasing him as a legitimate Top-4 defenseman in this league capable of playing big minutes.

2017 NHL Stanley Cup Final - Game Six Photo by Bruce Bennett/Getty Images

The Injury

The 26-year old blue liner was injured in Game 5 of the Stanley Cup Final against Pittsburgh. Although he played 24 minutes in the series deciding Game 6, it was clear he was limited by his injury. The extent of which was not revealed until just last week. Surgery to repair torn ligaments in his knee, comes with an expected 4-6 month recovery time, the team is hopeful to get Ellis back into the lineup by January. If the Preds have eyes on another playoff run, they will have the navigate the first half of their schedule with Ellis on the shelf.

What impact will the absence of Ellis have on the team?

The addition of Alexei Emelin from Vegas might have been a bit of a head scratcher, but GM David Poile made the move knowing that Ellis was likely to miss significant time to start the season.

We had a little bit of heads up, and that’s really one of the reasons why we got [Alexei] Emelin from Las Vegas to add to not only our depth but our quality of our defense.” ~ David Poile

Possession Impact

Lets first take a look at what the impact will be with Ellis out of the lineup. Recency bias is a real thing, and our initial assessment will surely be clouded by Ellis’ spectacular performance in the playoffs, but how does Ellis stack up against other defenders in the league in terms of puck possession?

Hockey data sites seem to be blinking off-line every few months, with new ones emerging to take their place. PuckIQ is one of the new entries, formed by a few Oilers fans. PuckIQ affords us the opportunity to evaluate players against varying types of competition. Quality of competition is a widely debated topic in analytics circles (see here and here). One of the measures of a Top-4 defensemen in the league is their effectiveness of playing against their opponents’ top players. PuckIQ simply labels this subset of players as “elite” so by evaluating Ellis against this elite competition, and that of his presumed replacement, we can get a better idea of what the Preds will be missing in his absence.

Looking at the chart above, you will see Ellis in the upper-left quadrant just below Adam Larsson, in what I have dubbed the “Help Me Baby Jesus” quadrant. Since he’s in the gray box, he’s within the first quartile, and by looking at the axis we can determine that he’s pretty close to league average. I filtered out all players who played less than 250 minutes against elite competition, which left us with a total of 147 players, or a little less than five defenders per team. Among those players Ryan Ellis was 47th in ice-time (solidly deployed as 2nd pairing d-man).

If we look at possession impacts, Ellis was just a bit below the league average of 47.4% finishing the season at 46.9 CF%. Using the qualifier of players deployed like Top-4 defensemen, Ellis is solidly in the middle of the pack of this group possession-wise with a solid sample size of 460 minutes. His closest comparables are John Carlson (WSH) and Adam Larsson (EDM).

If you’re looking for the other Nashville defenders in this chart based on possession, P.K. Subban is 7th, Josi is 14th and Ekholm is 15th. This is why we can’t have Matt Duchene, none of these four are going anywhere.

Since Ellis’ comrades on the D-Corps all rank higher than him in possession numbers, was it in fact Ellis who was “carried” all year long? Roman Josi has been a polarizing defender based on his possession impact throughout his career (so is his former partner, Shea Weber).

This past season Ellis played about 70% of his even-strength time opposite of Josi. Ellis’ WOWY with Josi is rather telling. Ellis was much better with Josi that he was without him, and Josi’s CF%, although in a very limited sample jumped from 49.7% to 55.6%. It’s worth noting however that this past season was Ellis’ only season below 50% CF, although he finished with a career high 38 points with 24 coming at even-strength.

Goal Impacts

Goal impacts are much more volatile because goals are rare events, but they are informative nonetheless. Using essentially the same chart as above by exchanging TOI for GF%, we see Ellis nearly at the cross-hairs of the chart. He’s in the cluster of four players just above Colton Parayko. His closest comparables here are Ben Hutton (VAN), Brady Skjei (NYR) and Cody Franson (BUF), which is a hell of a peculiar collection. He’s slightly below average in CF%, as referenced already, and slightly below average in GF%. He finished the season at 48.1% with the median being 51.2%. I’ve named this bottom-left quadrant as the “Get Me Off The Ice” quadrant. This isn’t to indicate that Ellis is particularly bad in this measures, he’s just slightly below average among the collection of players deployed most often against the opposing teams best players.

The Top Six

One of the benefits of a David Poile front office is his shrewd management of the cap. The Preds lost James Neal in the expansion draft, but other than his departure it was a pretty quiet offseason in Nashville. All seven of Nashville’s top defenders will return for this year. With Ellis out, I could see Ekholm and Subban making up the first pair and edging Roman Josi in even strength minutes. The bottom pair will most likely be Matt Irwin on the left side and Yannick Weber on the right side, barring any injuries in camp. That will leave Roman Josi with second pairing minutes with the newly acquired Alexei Emelin from Vegas through Montreal.

Montreal Canadiens v New York Rangers - Game Six Photo by Bruce Bennett/Getty Images

What About Emelin?

In Emelin the Preds are getting a left-shot d-man who’s five years Ellis’ senior and who’s recorded about half as many career points in 30 more NHL games. Jack Han gave us a nice overview of Emelin’s game, albeit from two years ago. Since then Emelin had his possession numbers improve to the point where he’s been a net positive for his team over the last two seasons (don’t look at this game though). He’s also been tasked in Montreal with the most difficult zone starts on the team with over 56% coming in the defensive zone.

Last year he had the benefit (depending on who you ask) of playing with Shea Weber for the majority of the season. As you can see from Emelin’s WOWY chart below, the pair was a +5 in even strength goal differential, although not being on the ice for a whole lot of goal generation for their side. Their CF% together hovered just below 50%. Looking at Weber’s numbers away from Emelin, what should jump out to you is that Weber and the Habs generated only five less goals in just over half the ice time for a stunning GF% of 80.8%. Ironically both players had positive CF differentials away from each other, but Emelin was a net negative in goal differential away from Weber.

The disadvantage Emelin will have stepping into the Preds Top-4 this season is as a left-shot defenseman he will be shuffled over to the right side and be forced to play on his off-hand. Spending the bulk of last season with Weber he was able to play his strong-side, not the case this year. How much of an impact will that have on him? Based on his style of play, being a simple get it out of the zone and play responsible on your own zone kind of guy, he’s likely to be given the role of covering for Josi which could free him up a little more offensively.

HERO Chart

So how do we compare the two defenders? Ellis more offensively inclined and has been treated as much in deployment. Looking at their HERO chart below there is no real comparison in offensive output and shot generation. Ellis trumps Emelin in spades here. Where Emelin holds up though is in shot suppression. He will be no worse than Ellis in that category.

Zone Entries & Exits

Doing yeoman’s work tracking play in all three zones is Corey Sznajder (click here if you want to support his work). Part of Emelin’s poor shot generation numbers is directly tied to his inability to exit the defensive zone with possession. As written earlier by Jack Han (now of the Toronto Maple Leafs), Emelin is a guy who often chips the puck off the glass or dumps it to center ice. Although limited by sample size (there is only so much Corey can do) we see Emelin markedly at the bottom of this list of defenders on either team last year with 100+ zone exits with an “exit with possession rate at just 25.4%”, a full 8% lower than anyone in the Preds Top-6 last year. This means when Emelin created the exits, he took the easy and safe way out rather than creating a passing play out of the zone.

At the top of the chart you see Roman Josi, the only defender on either team over 50%. The simple presumption being, if these two are defensive partners for the first half of the season Emelin would be wise to try to work the puck to Josi to make the zone exit rather than blandly getting the puck out to center on his own.

Zone entry defense is an area where Emelin excels (with the limited data available). It was well established several years ago by current Carolina Hurricanes director of analytics Eric Tulsky that carrying the puck into the offensive zone is far more likely to generate offensive opportunities than dumping the puck into the zone. Conversely preventing carry-ins has the opposite effect for the defense. If you prevent carry-ins you in theory should allow less shots on goal.

With the data available from last season, in 145 entries against Emelin the opposition generated 56 shots for a shot rate of 38.6%. On the flip side Ryan Ellis allowed teams entry into the zone 139 times with 86 shots for a shot rate of 61.9%. I dont want to get too carried away with such limited sample sizes, but the difference between Ellis and Emelin is rather striking.

So What?

So how do we make sense of all of this? First I think it’s safe to say the Predators will be fine. Ellis is indeed a Top-4 defender in the NHL and no team in the league wants to give up the services of such a player, but if there is a team in the league well-suited to sustain such a loss, it’s Nashville. With Subban, Josi and Ekholm in the fold, each of which could be considered top-pairing defenders on their own, Nashville is unique in this regard.

If we can say anything about Alexei Emelin, it’s that he plays the role of shutdown defenseman. He’s effective at limiting zone entries, which lowers his overall Corsi Against. He was above average (76th of 196) in this category among all D-men with over 500 even strength minutes played last year. He’s no Niklas Hjalmarsson in this regard, but he’s not going to get caved in either; he’s serviceable. We can reasonably expect teams (presuming they care about this) to target Roman Josi on zone entries more so than Emelin. Once the puck is in in the zone, we don’t want Emelin to try to break it out. It’s best he gets rid of the puck to Josi to get the transition game going.

His zone exit tendencies however do limit the amount of offense going the other way. This reliance on a teammate to exit the zone will put more burden on Josi to make it happen but could also be a catalyst for more offense by him if he can carry the mail. If Nashville can make effective plays through the neutral zone they shouldn’t stagnate without Ellis around doing the work.

We haven’t touched on the power play, but Ryan Ellis did chip in 11 points last year. He will need to be replaced by a right-handed shot who will play the left side of the ice. The Preds power play could be better, converting at a slightly lower than league average last year, and with three of their top four goal scorers all gone there will be changes with the power play anyway.

If we look back at both the charts used to evaluate Ellis’ possession and goal generation, Emelin slightly outperformed Ellis in both measures with both results closely resembling Shea Weber, not uncommon considering how much they played together last year. It would be hard to parse one from the other in a one year sample, but safe to say Emelin will be fine playing with Josi and won’t be outmatched by the opposition. He’s a solid veteran defender who won’t do anything flashy on offense but should do well enough in his own end.

Fear not Preds fans, while Ellis is a likable guy, with his warrior status confirmed in the Cup Final, the Predators will manage without him while his injury heals and he completes rehab. Maybe the time off will give Nashville a fresher, stronger Ryan Ellis ready to repeat his playoff performance from last spring.