Delta SOT for Defensemen

The other day I posted about Delta SOT scores for the Leafs forwards based on the previous 3 seasons in the NHL.  The stat (an invention of Puck Prospectus' Tom Awad) serves to measure the +/- rating on scoring chance generation or allowance while a given player is on the ice.  Players with higher scores are on the ice for a larger number of good scoring chances than they allow.

I left a look at the Leafs blue line for a couple of days, and hopefully we can come at this second set of numbers with a slightly increased level of understanding.  To assist in some of the discussion this time around I'm going to add some explanation of the adjustment calculations.

Situation Adjustments

This adjustment compensates for the zone in which a shift starts, and the percentages of faceoffs won by the team of the player in question.  Defensive players often start in the defensive zone and then surrender a larger number of scoring chances against.  That being said, the adjustment factor will not necessarily adjust a defensive player into a positive DeltaS score because defensive specialists often lack the offensive skills that lead to the generation of scoring chances at the other end of the ice.

Opposition Adjustments

This adjustment is just calculated as the average of the opponent players' Delta S scores.  This may be a simplification of opposition effects, but in the end it should not be as large an impact as teammate factors, because it is basically a given that an NHL player will skate the majority of their ice time against a wider variety of opponents than teammates. With this and the previous adjustment we now have Delta SO.

Teammate Adjustments

Awad took each player’s Delta SO and calculated the amount of 5-on-5 time that they spent with each of their teammates. To determine the adjustment he then subtracted that teammate’s Delta SO per minute, multiplied by the number of minutes the two players played together, times 0.2.

For example, if Alex Ovechkin, Nicklas Backstrom, Alexander Semin, Mike Green and Jeff Schultz all played together all the time, and each one had a Delta SO of 10 in the same amount of ice time, then this process would give each of them a Delta SOT of 2 (subtracting 10 * 0.2 four times from each of them). Conversely, if Ovechkin played half of his time with these four players, and half of his time with 4 other players who each had a Delta SO of 5 (again in the same amount of ice time), then his Delta SOT would be 4.

So now that we have a more detailed explanation (which I hope adds to, or clears up, the discussion that occurred the other day) let's see how the Leafs defenders fared over the past 3 years in respect to the number of scoring chances they've been on the ice for versus the number they've been on the ice against.

So what does this tell us?  On the negative side of the docket, Jeff Finger's trade value may never climb above zero.  He appears to be a liability on the ice in terms of scoring chances against.  Dion Phaneuf also needs to rebound from two poor seasons of Delta SOT scores.  His time in Toronto at the end of the season may bode well in that regard as he actually registered a Delta SOT of +0.9 with the Leafs, so perhaps he is settling down in terms of the number of chances he's allowing.

On the more positive side of things, it appears every other Leaf blue liner has seen a steady increase in their Delta SOT scores over the past 3 seasons.  Obviously Carl Gunnarsson and Luke Schenn are still in the early going of their careers, but Gunnarsson's +0.3 Delta SOT score at least bodes well for next season if he makes improvements.  Similarly, Schenn's scores improved drastically from year one to year two, as he played slightly more sheltered minutes with superior teammates against easier opposition.  Overall the net impact was to minimize the chances against while increasing the chances at the offensive end.

Mike Komisarek seems to have been placed in a less defensive role if his Delta QS adjustment is anything to go by.  He also faced easier competition, so it will be interesting to see how he's used next season.  Despite facing some of the team's toughest competition, Francois Beauchemin put in his best season out of his past three from the perspective of producing good scoring chances.  Hopefully he can maintain that level of play.

Brett Lebda's numbers also make lots of sense.  He was playing sheltered minutes up until this past season, often skating with superior teammates (which makes sense on Detroit).  Then he dropped down the depth chart, and was seeing a reduced quality of teammate.  Despite that fact, his Delta SOT number improved every year over the past three.

In the end, the fact that the Leafs Defense generally appears to have had solid Delta SOT scores last season (particularly in comparison to the forwards), leads to the conclusion that overall the team wasn't as bad defensively at 5 on 5 as it might appear from their record.  This should serve as a further indictment of the shoddy goaltending of Vesa Toskala, but hey... we already knew that didn't we?

Feel free to contribute discussion below.