On Kovacevic's Struggles Away from Jonas Siegenthaler

It seems as though No. 8 was a byproduct of phenomenal play by a now-injured Siegenthaler.

From the beginning of the season until Jonas Siegenthaler suffered a long-term injury, he and newcomer Johnathan Kovacevic combined to form the most potent defensive pairing in the NHL. In fact, until the two were separated during the Devils’ general struggles after the holiday break, many models rated Kovacevic as a better defensive defenseman than Siegenthaler. It wasn’t until after that pair was broken up that those models corrected their ratings to show that the latter buoyed the former.

That isn’t to say that Kovacevic has been a bad defensive defenseman this season in isolation. As per HockeyViz, he is a direct cause of the Devils allowing 6% fewer xG per hour than league average. You can see the isolated heatmap below:

via HockeyViz

This heat map indicates that he is a strong crease-clearing defenseman, which tracks with the eye test. He rarely gives space to forwards who are crashing the net, and he has an extremely active stick in breaking plays up as they form in the defensive zone.

Looking at his microstatistical profile, he also excels at two things: puck retrieval and preventing zone entries:

via AllThreeZones

He gets targeted a good bit more than average and largely does a great job at preventing chances when targeted. He is an aggressive defender on the rush, again using his active stick to break up those plays and disturb passing plays as they happen. In terms of retrievals, he’s relatively average at actually retrieving the puck, but is great at making plays that get the puck out of the zone once he does retrieve it.

All this is to say that Kovacevic is still a solid defensive defenseman, even if the results haven’t necessarily been there away from Siegenthaler, who was having inarguably the best defensive season in the NHL before he suffered an injury. 

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Kovacevic’ On-Ice Struggles With Other Defensemen

For comparison’s sake, let’s first talk about how successful he and Siegenthaler were as a pairing in their 748:24 together.

Among the 71 defense pairings with at least 400 minutes of 5v5 play this season, Kovacevic and Siegenthaler allowed the fewest expected goals against per 60 minutes (1.84). The Devils only allowed 17 goals in that time, which amounts to roughly 12.5 full 60-minute games. That’s 1.36 goals against per 60 minutes (GA/60).

Ridiculous.

Luke Hughes

Kovacevic and the dynamic Luke Hughes have partnered up this season for a grand total of 71:09. Head coach Sheldon Keefe paired them up semi-recently, I would assume in hopes that Kovacevic would unlock some of that defensive stalwartness in L. Hughes’ game that he had in mid-December. That… hasn’t been the case. The two haven’t proved to have an iota of synergy together.

They sport a 33.33% goal share (GF%), and the underlying metrics reflect that. With them on the ice, the Devils are producing just 1.96 expected goals for per 60 minutes (xGF/60) and are allowing 3.69 xGA/60, giving the Kovacevic-Hughes pairing an abysmal 34.64% xGF%. They control just 46.03% of the scoring chances and 33.33% of the high-danger scoring chances as well.

I’m not quite sure of the issue with this pairing, to be honest. As established in the introduction, Kovacevic is a solid enough defender in isolation. Luke is Luke, a talented, dynamic presence who can contribute on both sides of the puck, especially when things are going his way. Instead, they both look like lost puppies out on the ice, unsure of who to cover. It brings out the worst in both players.

Brenden Dillon

Next up is Brenden Dillon, with whom Kovacevic has spent 46:12. I would imagine the purpose here is a shutdown pairing, as even despite the underlying statistics, there is a stigma around Dillon that he is a defense-first guy. This, too, hasn’t worked out well, though the results aren’t quite as harrowing as they are when Kovacevic spends time with L. Hughes.

When Dillon and Kovacevic are on the ice together, the Devils are allowing 2.83 xGA/60 while producing just 2.32 xGF/60. They are controlling the majority of the high-danger chances, surprisingly, but are losing the scoring chance per hour share 32.47-28.57.

Again, this was being deployed in a purely shutdown role, with the duo garnering just 22% of their starts in the offensive zone. That isn’t what Dillon provides, and Kovacevic isn’t strong enough defensively to buoy his own shutdown role regardless of who he’s with — he almost profiles as a sort of defensive passenger blueliner who can only really excel in his role when playing alongside a fellow defensive defenseman.

Dougie Hamilton

Last is Dougie Hamilton, who has spent 31:37 alongside Kovacevic. As with L. Hughes, I would imagine that the idea is to pair an offensively oriented defenseman with a defense-first guy, much like they’ve done with the Siegenthaler-Hamilton pairing that worked so well for so long. Again, Kovacevic doesn’t work in this role. At all.

In fact, this is probably the worst pairing of any Kovacevic pairings — the Devils are completely unable to get anything going offensively with him and Hamilton on the ice, producing just 1.24 xGF/60. They’re allowing a relatively normal 2.60 xGA/60, but the lack of offensive juice gives them an xGF% of 32.36%. There is no reason to ever experiment with that pairing ever again.

I’m not going to harp on his play with Simon Nemec for too long, simply because 1) Nemec has been pretty bad this season, and 2) they’ve only played about 13 minutes together, but that pairing didn’t work either. Seamus Casey isn’t worth mentioning here either because they’ve played fewer than three minutes together.

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Use Kovacevic-Pesce as the Shutdown Pairing

The only other defenseman Kovacevic has played adequately with this season is fellow first-year Devil Brett Pesce. The two haven’t quite lived up to the defensive aptitude that Kovacevic and Siegenthaler have, but they’re generally very good in that regard, sporting an xGA/60 of 2.32 while controlling 52.65% of the xG share.

My hunch is that this is because of Pesce’s inherent ability to mold his game to whoever he is playing with as a partner, something that, in my eyes, makes him extremely valuable as a player on this team in particular. He’s able to provide a steady balance to an offense-first player (Hamilton, L. Hughes), he tries to be the shooter on a pairing without one (Dillon), and, in this case, he is able to be that stalwart presence that he was brought in to be when put in a purely shutdown role. Until Siegenthaler returns — presumably around playoff time — Kovacevic should be stapled to Pesce and only deployed in a shutdown role.

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Devils Should Steer Clear of Re-signing Kovacevic

The Devils are in no shortage of defensive defensemen, with Siegenthaler and Pesce proving to be apt in that role. Kovacevic was a nice story at the beginning of the season (until the holiday break) but has largely been exposed since. If he is only deployable with one (maybe two) partners, there are better routes the Devils can take. With two blue-chip prospects on the right side in the pipeline (Nemec and Casey), the Devils would be short-sighted to prefer Kovacevic over either of those players. Let him walk into free agency.