In today’s sabermetrics and hockey post, I will combine team and zone start effects to adjust Corsi Numbers. The Corsi Number is the difference in the number of shots directed at goal (shots on goal, missed shots and blocked shots) for a team and its opposition. It is a strong predictor of puck possession in a game.
There are several reasons why looking at raw, unadjusted Corsi Numbers can be flawed. The biggest two are team effects and individual usage of players. If a player is on a good team that possesses the puck well, he is likely to have a good Corsi Number as a result of his teammates. The reverse is true on a bad team. If a player is consistently used for defensive zone starts and not offensive ones, he is more likely to have shots directed at his goal and vice versa for players who get many offensive zone starts.
In 2007 Sami Pahlsson, then of the Anaheim Ducks, looked like he was an NHL star. He finished second to Rod Brind’Amour for the Selke Trophy and some made a strong argument that he should have won. Pahlsson was part of the Stanley Cup winning Ducks squad, where he led the playoffs in +/- despite playing a shutdown role against the toughest opposition to the Ducks. Some even suggested he should win the Conn Smythe Trophy. Many people thought it was just a matter of time before Pahlsson won his Selke, but it hasn’t happened.
Injuries derailed him in his next season. Pahlsson only managed 56 games played and then his contract status led to his moving around the NHL. As a free agent to be, he was traded to the Chicago Blackhawks along with Logan Stephenson for James Wisniewski and Petri Kontiola in a trade deadline deal and then he signed as a free agent in Columbus.
This is calculated by observing which players are on the ice at faceoffs by zone. The players ranked here have the largest difference between their faceoff starts in the defensive zone and those in the offensive zone. For this study, neutral zone starts are ignored. The players here played tough defensive roles with their respective teams. This will hurt them in both their offensive numbers and in their puck possession stats (+/- ratings and Corsi). Thus it is necessary to take their zone starts into account when trying to rank players properly by any of those metrics.
In 2007 the Nashville Predators were in a bad situation. Their owner was Craig Leipold, who wanted out. Jim Balsille made overtures about buying the team and moving it to Hamilton, but Leipold instead accepted an offer form $193 million (less than Balsille offered) from a local ownership group. As payment for not selling the team to Balsille, Leipold wound up as the Minnesota Wild owner, which is a team in a much stronger financial situation than Nashville.
It turned out that the local group was not in good shape. William “Boots” Del Biaggio, who held a significant minority share, turned out to be a fraud. The NHL had not investigated his background significantly and it turned out he did not have the money he claimed. Del Biaggio declared bankruptcy and went to jail, but the question of who owned his 26% share of the team remained a question looming over the team.
Salary arbitration hearings began on Tuesday. Here is the arbitration schedule. Notice that most cases have been settled before the actual hearing. So far only two cases have been heard. On Tuesday, Jannik Hansen of the Vancouver Canucks had his case heard and yesterday Clarke MacArthur of the Atlanta Thrashers had his case heard. Usually there is a 48 hour delay after a case before the result is announced. The Hansen case has yet to be resolved. However, the MacArthur case was heard quickly and we have a result.
Clarke MacArthur was awarded a $2.4 million contract, but Atlanta walked away from the deal instead of accepting it. This was rumored before the arbitration hearing occurred.
In the off season, any controversy that keeps hockey in the news is a good thing. At least it keeps people talking about it. The NHL has its controversy. They rejected the contract Ilya Kovalchuk signed with the New Jersey Devils as being an attempt to circumvent the salary cap. Of course they are right that the 17 year term with six years at the end where Kovalchuk is paid less than $1 million is done to keep the average annual salary down. The $6 million salary cap hit exists only on paper and it is almost a certainty that Kovalchuk will retire long before the contract expires, thus making his average payment higher than the salary cap reported figure.
The problem is that the NHL has accepted several contracts that are set up to reduce the salary cap hit by adding on several low paid years at the end when the player in question is likely retired. I think the worst one before Kovalchuk is Marian Hossa`s contract with Chicago.
Yesterday the highest profile free agent of the 2010 summer, Ilya Kovalchuk re-signed with the New Jersey Devils. He signed a 17 year pact worth $102 million. This gives him an annual salary cap hit of $6 million. This is a glorious example of legal contravention of the salary cap. Nobody seriously believes that Kovalchuk will still be playing in the NHL at age 44 when the deal ends. Nobody seriously believes that Kovalchuk will play for the 17 year term or have an annual average salary as low as $6 million.
That said there is nothing the NHL can do about the deal right now. There is significant precedent for these long term deals with declining pay in the sunset seasons to keep the annual salary cap hit down. There are more than a handful of players signed to these deals who are not expected to complete them.
In today’s sabermetrics and hockey post, I am taking a temporary break from Corsi numbers to look at zone starts. Eventually I will adjust Corsi Ratings to include zone starts, but today I want to look at zone starts themselves. Zone starts are a measure of how easy or tough defensively a player’s assignment is. The players on the ice for each faceoff are recorded and the zone in which it occurs. Players who play more offensive faceoffs than defensive ones have less defensive responsibility than those that play more defensive faceoffs than offensive ones. When it comes to Corsi Ratings, players who are put on the ice for faceoffs in their own zone will do worse than players put on in the offensive zone, because it is far easier for a shot to occur in the zone where the play starts.
There is nothing bad about being put on the ice for a significant number of offensive zone starts. It is a sensible way to use an offensive player, but it is worth noting that player does not have the defensive responsibility of most NHL players.
Yesterday, I listed the top 20 players by team adjusted Corsi ratings. This is a strong indicator of puck possession which measures the difference in the number of shots directed at goal (shots on goal, missed shots and blocked shots) by a team and their opposition in 5 on 5 situations when a given player is on the ice. This number is strongly team dependent as good teams tend to possess the puck more than weak ones. Thus a team adjustment is made to better compare between different teams.
This adjustment is not perfect. It does not take into account the usage of a player (defensive vs. offensive) or the quality of his teammates or opposition, but it goes a long way toward identifying some of the best and worst puck possession players at even strength. That is not always the same as identifying the best hockey players because there is more to hockey than even strength puck possession (for example special teams play).
My next sabermetrics and hockey post is to correct the top individual player’s Corsi Ratings for team effects. One look at the top Corsi Ratings from last season shows that there are an unreasonably high number of Chicago Blackhawks represented (the top three and six of the top 20 are Hawks). This is because Chicago has the best team Corsi in the league and it is easier to have a good individual number when all your team has good ratings.
In order to adjust these Corsi Numbers for team effects we use the same method used for counting +/- ratings. Thus we can rank individual player’s puck possession via Corsi (difference in shots directed at goal by a player’s team and their opposition in 5 on 5 situations) without team effects distorting our numbers. We still have issues from individual player roles (some are used more defensively and others offensively) which we can try to remove with a further adjustment.
About The Puck Stops Here
Who am I? A diehard hockey fan.
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