Nashville SC

How important is Walker Zimmerman to Nashville SC’s set-piece success?

I’ve long been on the record maintaining that, as good as Walker Zimmerman may be, Dave Romney is just as crucial to Nashville SC’s success on defense. Certainly, their complementary natures (the steady hand of Romney tempering the risk-taking of Zimmerman) play a major role in that. But I’ve long felt that Zimmerman’s 2020 MLS Defender of the Year Award had much more to do with 1) wanting to recognize somebody for NSC’s near-unprecedented defensive success in an expansion year, and 2) his goal-scoring and high-energy style that put Zimmerman in the highlight reels much more than his companion.

I will continue to assert that Romney is criminally underrated (and if it’s a zero-sum game, that takes a bit of shine off Zimmerman, I guess). But the reigning DPOY’s importance to Nashville has been exposed in his absence.

Set piece dominance

Zimmerman is known for his goal-scoring, particularly on corner-kick (and other set-piece) opportunities. His first goal in MLS came from a header after a free kick near the corner flag. The first goal in Nashville SC history came as part of a corner sequence:

Nearly all of his goal-scoring production has come via the set piece, in one way or another (though he’s added a bit more attacking from the run of play to his game).

What’s just as – if not more – important, though, it what he does defensively on set pieces. The birth of his son and then a current stint of international duty have provided a glimpse into what Nashville SC is with and without Zimmerman patrolling the penalty area when opponents are trying to put the ball in Joe Willis’s net.

We had a lengthy discussion on this week’s podcast about this topic. Check it out here, though the information is easier to present in a written format.

Here are Nashville SC’s defensive numbers so far this season, with a few interesting splits. Keep in mind his time off the pitch has happened only in the past five games: the final 32 minutes against New York Red Bulls, the first 78 minutes against CF Montreal, and the entirety of the Toronto FC and Atlanta United contests (he played the whole Philadelphia Union game).

With Zimmerman Without ZimmermanTotal
Minutes8703091179
xG against8.082.0410.11
Goals against8513
Corner/set-piece
xG against
0.990.961.94
Corner/set-piece
goals against
044
Data via American Soccer Analysis with some additional work needed to get the on/off splits right.

When Zimmerman is on the field, opponents are creating at a slightly higher rate overall (0.89 expected goals per 96 minutes, compared to 0.63 xG per 96 minutes when he’s been out). Overall, though, they’re converting on their expected goals at a much higher rate. Teams are approximately at their xG totals when he plays, and they’re at 2.5 times their xG totals when he’s off the pitch!

Obviously, there is some sample-size and game-state noise here. And it’s also tough to quantify an individual defender’s contribution to xG: does it reflect poorly on him individually that opponents generate shots? Or good that they find shots and don’t convert?

The Zimmerman effect is even more pronounced on set pieces, of course. Anecdotally, you can think back to Toronto’s corner-kick goal, as well as the one scored by Montreal and both by Atlanta United (one an attacking-area set-piece, rather than a corner, but the point remains the same). It’s hard to imagine Nashville giving up goals like that, but without Zimmerman’s aerial threat, service arrived cleanly at the targets, NSC opponents won jump balls, and NSC has given up its only four set-piece goals without the reigning DPOY on the pitch.

Not only is Nashville giving up more opportunities via set-piece per minute when he’s not around (in part because his defensive range allows for fewer fouls and fewer clearances for corners, but also because opponents are unable to get the shots in the first place), but the lack of a challenge from Zimmerman is seeing the conversions… actually happen at all.

Feels so empty without me

So, we know that Nashville has set-piece issues without Zimmerman on the field. Indeed, both Gary Smith and Jack Maher were open about that after the Toronto game. His replacement has noted a desire to learn from Zimmerman, but it’s fair to say he’s not there yet.

“Walker is an absolute beast in the air,” Maher admitted after the Toronto FC win. “I think that was something that we were missing today. Knew that I could step up on a set piece, and found a way to help out whatever way I could [offensively].”

Maher wasn’t personally outjumped for the goal in that game, but he was just a couple days later to create CF Montreal’s lone score in a 1-1 draw.

“It’s an identical spot – almost identical – that we conceded mid-week,” Smith said. “We tried to negate that area. Jack’s doing a fantastic job, I’m delighted with his performance, but he was in that front zone that may well have – with a little bit more experience – might have just taken a little more aggressive step.”

That aggressive step may not necessarily mean winning the header. But it can mean throwing the attackers balance off just enough to prevent clean contact and a shot on goal – or at least a shot that has enough power to beat Joe Willis.

Zimmerman’s leadership and physical presence (Alex Muyl outmuscled and nobody in the middle of the six-yard box aware enough to block the shot) could have prevented Atlanta United’s first goal. The second was once again a pure out-jump situation that Nashville hasn’t fallen victim to when Zimmerman is on the field. He’s so dominant in the air that NSC can spread its other numbers around a little more.

Papering over

The reality of Nashville SC’s situation is that Zimmerman won’t be returning to the team until after the Concacaf Gold Cup. Even if the United States Men’s National Team were to lose Group B (this will not happen. Knock on wood), he’s unavailable for this weekend’s game against Chicago Fire, and likely a midweek trip to Columbus Crew thereafter. More realistically, the Americans not only advance out of the group, but stand a strong chance of winning a quarterfinal knockout-round match. That means a semifinal game July 29 – and two more games (against FC Cincinnati and away to Toronto) without Zimmerman. If the US makes the Aug. 1 final, he’d almost certainly miss the Aug. 4 trip to New England, as well.

So what can Nashville do without him?

For one, there’s a reasonable hope that Jack Maher’s MLS experience – quadrupling his career minutes in MLS over the course of the past three weeks – will provide enough benefit that he makes the decision Gary Smith referred to above when put in the same situation.

Nashville is also playing against a non-murderer’s row of set-piece teams: while New England leads the league in expected goals from corners and set-pieces, and Chicago is fifth… Columbus (22nd of 27 teams), Cincinnati (13th), and Toronto (8th) are run-of-the-mill. And all of them except Toronto are under-achieving their expected goals from those situations. Meanwhile, Nashville is third in allowing set-piece xG (as noted above, it’s the conversion that’s been an issue on that end of the field). Minimizing the number of opportunities these teams generate in the first place is a good step toward preventing them from scoring.

In the end, though, Nashville needs better performances in set-piece defense without Zimmerman, and a touch better luck to make those performances come through. Because when he returns, you can be certain that the Boys in Gold will return to the realms of the elite.

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