Should Tomáš Hertl Play Center or Wing?

Tomáš Hertl was drafted to play center, presumably. The summer the Sharks drafted Hertl, Joe Thornton was entering his 33rd year as a human being and seventh season past his physical prime. The Joe Thornton era’s end wasn’t in sight, but it made sense for the team to start collecting centermen who might populate the team’s depth lines.

One of Hertl’s best qualities was that he could play center and wing. Hertl has played both positions under both the Todd McLellan and Pete DeBoer regimes. Because he’s a good player in his own right — he has only scored at the rate of a third-line player, but he drives shot differential like a first-line guy — he’s succeeded at both positions.

This season, the team rebounded from an ugly 0-2 start and are currently back at .500. During the first two games, Hertl centered a third line with Joel Ward and Timo Meier, which was awful, then a line with Meier and Donskoi, which was outstanding. The Sharks lost both games and DeBoer shuffled the proverbial deck, moving Hertl up to Logan Couture’s wing, where the duo has enjoyed immense success in the form of shot and expected goal differential.

So far this season, the Sharks are 0-2 with Hertl as a center and 4-2 with him as a winger. The underlying statistics back up the stronger record since the atrocious start. It seems some attribute the improved shot and goal differential to Hertl’s move to the wing. Is that really the case? Where should the Sharks play Hertl if they’d like to ice the most optimized lineup this season?

(An aside: Not enough people are crediting the infusion of younger blueline talent for the Sharks’ recent about face. The Dillon – Heed and Ryan – Burns pairings are playing amazing hockey right now. Those changes are at least some of the impetus behind the team’s success of late.)

Hertl’s Results Since the 2013-14 season

The above chart shows the six lines Hertl has played on between the 2013-14 season and the 2016-17 season that played at least 100 minutes of 5v5 time together (with the exception of the Hertl – Tierney – Wingels line, which played 99 minutes and 50-some odd seconds together), per corsica.hockey.

CF% = Corsi for (or shot attempts for) percentage. This is the percentage of shots the Sharks attempted while that line of forwards was on the ice at 5v5. Shot attempts are important because they’re the best predictor of future goal scoring. 50% is average, 55% is really good and the wild 60+% the Thornton, Burns, Hertl line generated is otherworldly.

ROT CF% = Rest of team corsi for percentage. This is the percentage of shots the rest of the team attempted (the team’s percentage while those three forwards weren’t on the ice).

xGF% = Expected goals for percentage. Expected goals tell us about the shot quality these lines offered the team while they were on the ice and the percentage of total goals the Sharks could expect to score with that line skating.

ROT xGF% = Rest of team expected goals for percentage. This is the percentage of goals the team could expect to score at 5v5 while the Hertl line was off the ice.

There are two notable exceptions on this graph. The Hertl – Thornton – Burns line was the juggernaut of all juggernauts. Of the 336 lines to play at least 200, 5v5 minutes together between the 2013-14 and 2016-17 seasons, that line leads the pack in terms of shots for and expected goals for percentages. Then there’s the Tierney – Hertl – Wingels line. They were bad, but the rest of the team around them was only average.

The other four lines all had very similar shot attempts for percentages, falling between 55.8 percent and 57.5 percent. The Nieto – Hertl – Wingels line was the only line that wasn’t able to routinely turn those shots into dangerous chances.

Lines on which Hertl was a winger had the largest differences from the rest of the team in terms of shot attempt and expected goals for percentages. That suggests that, while these lines were very good, the rest of the team may not have been as balanced as when the team had Hertl skating as a center.

On the whole, it appears the Sharks fared pretty well with Hertl at center or on the wing. The Sharks generally performed better when Hertl was a winger, but the rest of the team seemed to suffer a bit more because the forward depth was depleted.

The fact that a lot of these results are fairly similar says a lot about Hertl. After all, playing alongside Brent Burns and Joe Thornton is much different than centering Matt Nieto and Tommy Wingels.

Quality of Competition and Teammates Matters

This is a look at how the Sharks did with each player on the ice at an individual level. This measurement isn’t great — each of these guys played with four other skaters at any given moment, so his results are also tied to those teammates. Still, a cursory look helps us understand the differences playing with Burns vs playing with Wingels.

This article tells us that the quality (as defined by time on ice) of a forward’s linemates and the quality of the defenders he plays against have the biggest impact on his on-ice results. This graph doesn’t look at time on ice, but it does try to understand how much those teammates contributed to the results on Hertl’s lines.

GF% = Goals for percentage. This is the percentage of all 5v5 goals the Sharks scored with a given player on the ice.

ROT GF% = Rest of team goals for percentage. The percentage of goals the Sharks scored when this player was off the ice.

Burns, Thornton, and Pavelski offered Hertl ice time during which he’d be on the ice for a higher proportion of shots, expected goals, and goals than the rest of his teammates. Ward, Tierney, Nieto, and Wingels all offered ice time for Hertl during which he could expect to attempt the same amount of shots and score the same proportion of goals as the rest of his teammates. Ultimately, however, those lines — lines on which Hertl served as a center — converted chances at a much lower rate than their teammates.

Couture’s shot attempts and expected goals rates were more similar to the teammates for which Hertl served as a center. Still, Couture ice time meant a higher proportion of actual goals than ice time with other teammates.

As a winger: Hertl played with teammates who were better at scoring goals and better at controlling play than the rest of the team.

As a center: Hertl played with teammates who were worse at scoring goals and average to just-above-average at controlling play compared to the rest of the team.

The image above is fairly representative of Hertl’s time as a winger with guys like Thornton, Burns, Pavelski, and Couture. On those lines, he played more against competitors’ top defense pairings than the average skater, but he also played with the Sharks’ best forwards.

Skaters like Tommy Wingels and Joel Ward were worse than the Thorntons, Pavelskis, and Coutures of the world at helping the team control play. They played against opponents’ bottom pairs more than the average skater, but they also saw about an average amount of time vs. first- and second-pairing defensemen.

Conclusion: This Isn’t Cut and Dried

With the exception of a bad line on an average team and a ridiculous line on a very good team, the results the Sharks enjoyed with Hertl as a center didn’t vary drastically from the results they saw with him as a winger. One could argue that the lines Hertl played on as a winger were generally more effective than the lines on which he played as a center. However, lines with Hertl as a winger saw the biggest drop offs to the rest of the team’s results.

As a winger, Hertl typically played with the Sharks’ best forwards against opponents’ top defense pairs. As a center, Hertl played with average teammates against a wider variety of defense pairs and still did well for the most part.

The conclusion is that a few things can all be true.

1. The team will likely succeed with Hertl at either position because of the strength of the rest of the team around him.
2. If the Sharks keep Hertl as the second-line winger, they’ll have to do a better job optimizing the bottom six forwards, because Chris Tierney isn’t capable of playing effective third-line minutes, and both the third and fourth lines have floundered in Hertl’s absence from the bottom six.
3. Because Meier and Donskoi represent top six talent but neither can play center, the team is likely going to be better off this season using one of those two alongside Couture and moving Hertl back to the third line where he can help spread out the team’s talent more evenly.
4. Hertl can play both positions. If the team wants to understand which of those two positions better suits Hertl, they’ll play him as a center with teammates who offer the same play-controlling ability as the forwards with whom he’s played winger. (Such as a Donskoi – Hertl – Meier line). Until then, the differences in teammate quality are likely to make Hertl seem more effective or dangerous as a winger. As a result, Hertl might seem better equipped to play wing, but the rest of the team will likely suffer due to losing depth among the third and fourth lines.

This season, Hertl should play