Controlled Situation Corsi: Patrice Bergeron, David Krejci, and the Set Play

Screen Shot 2014-09-09 at 7.01.06 PM

I wrote last week about the Bruins’ struggles following offensive zone faceoff losses. Obviously, Shawn Thornton played a part in that, but a fourth line can only get so much ice time, and obviously there was a bigger issue. When I looked over the numbers from the past few years, it became clear that David Krejci and his linemates, who received a large portion of the offensive zone starts, were hurting the team the most in those situations. Considering Krejci’s new 6 year, $43.5 million contract, and the ongoing debate over whether he or Patrice Bergeron is truly Boston’s number one center, I decided to look briefly (update: not so briefly) at the breakdown of their numbers and where such struggles might be coming from. First of all, here are the numbers.

Screen Shot 2014-09-09 at 5.45.55 PMThe chart was built to hold formulas, rather than to be clear to readers, so allow me to explain. These cells represent Bergeron’s and Krejci’s corsi for (or shot attempt differential) percentages, respectively, in the 21 seconds following defensive zone faceoff wins, the 37 seconds following defensive zone faceoff losses, the 29 seconds following neutral zone faceoff wins, the same for losses, and then the 37 seconds following offensive zone faceoff wins, and the 21 seconds following offensive zone faceoff losses. Why those specific numbers of seconds? It is after those amounts of time that Tyler Dellow found that the effects of faceoff locations and results were nullified. The final column shows open play corsi, which is essentially zone start and faceoff result-adjusted corsi, except with a slightly more limited sample size.

We could easily just examine these totals from the past four seasons, but considering we are trying to evaluate for the present and future, I wasn’t satisfied with weighting these seasons equally, so I borrowed the Marcel forecasting system, courtesy of at various points Tom Tango, Eric Tulsky, and most recently garik16, weighting the most recent seasons more highly than those further in the past. Here were my results.

Screen Shot 2014-09-09 at 5.46.27 PMAs you can see, the impact isn’t huge, but I wanted to be sure that we weren’t focussing on problems from years ago that have since been resolved. Anyway, it’s clear from these numbers – and the knowledge that Krejci doesn’t play against tougher competition or with significantly worse linemates – that Bergeron is the better possession player. The areas in which Krejci struggles compared to Bergeron are following neutral zone faceoff wins and following offensive zone faceoff losses. Considering, however, that the league average CF% following neutral zone faceoff wins is just over 60%, the takeaway from those results is clearly that Bergeron is a god among men, rather than that Krejci is horrible in those situations. Following offensive zone losses, however, is another matter. The average CF% in the 21 seconds following offensive zone faceoff losses in 2013-14 was 56.71%, so it’s clear that that is an area in which Krejci’s line needs to improve.

I dug into the video to try and find out why.

And I didn’t find much. Whether it was Bergeron or Krejci, the B’s would be aggressive and rightfully so, sending the two wingers to pursue the puck. Sometimes they would get to the puck in time, and sometimes they wouldn’t. I didn’t see anything that indicated a particular flaw in tactics or technique. Until I did. Maybe.

Screen Shot 2014-09-08 at 7.59.39 PMOn certain occasions, Milan Lucic, the LW, would line up directly behind Krejci, at the top of the circle. The hope from such a play would be that Krejci would win the faceoff straight back, and that Lucic would have an immediate chance for a shot on goal from the high slot. Unfortunately, when Krejci lost the faceoff, this would happen.

The two forecheckers would be far too late arriving. A zone exit would be practically a certainty. This play was used fairly regularly last season from what I saw. There were two conclusions I drew from examining this admittedly small sample of plays (I watched offensive-zone faceoff losses from every 10th Bruins game last season).

1. Krejci and Lucic weren’t in sync on these set plays.

Obviously, after watching just under a dozen of these, it is hard to tell whether I simply got a poor sample or if there was a legitimate problem, but from what I saw, there were a few too many faceoff wins that ended up like this.

Besides bad luck, I notice that Lucic sets up a little bit too far to the left. Considering Krejci’s right handedness, and therefore his stick positioning when he makes contact, it is inevitable that even with a fairly clean faceoff win, the puck will trend right, at best winding up in Lucic’s skates. It would take the cleanest of faceoff wins, consistently, for Lucic’s positioning there to work, and very few players can win faceoffs that cleanly that consistently.

2. Bergeron is a faceoff god and Krejci is a merely above-average.

Bergeron can certainly win clean faceoffs, but his mastery is such that even when he doesn’t do so, he can still recover the puck and put it in a place where his teammates can make something happen. Notice here how Bergeron gets the puck out of the scrum to Marchand (stationed further inside), who makes a heads up play, recognizing he doesn’t have the puck and shuffling it over to Krug, for a solid chance.

So is the play worth it?

Bergeron’s mastery of faceoffs is critical to the decision-making surrounding this play because losing the faceoff is a free zone-exit. If I were the Bruins, I’d be examining every one of these situations from every game (rather than every 10th game) to determine for both Krejci and Bergeron a) the CF% and scoring chance % in the seconds directly following a faceoff win with the play implemented, b) the same with the play not implemented, c) the CF% and scoring chance % with the play following a faceoff loss, and d) the same without the play. You get the idea. The reason is that by using Bergeron and Krejci’s faceoff percentages – 58.6 and 51.2, respectively in 2013-14 – one can determine the expected value of each offensive zone faceoff with and without the play, and thus come to a conclusion as to its effectiveness.

Inevitably, considering the nature of the play, that expected value is bound to be far higher for Bergeron than for Krejci, even if they were both equally adept at pulling it off after faceoff wins. For now, it is clear that Krejci’s numbers following faceoff losses suffer as a result of this play, and one can only guess as to whether that gap is made up following wins. My guess would be not.

One thought on “Controlled Situation Corsi: Patrice Bergeron, David Krejci, and the Set Play

  1. Pingback: FlightZone: Wheeler Clears the Air | World Sport News

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