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Dustin Byfuglien: Back to business as usual or something new?

There has been lots of talk that we are seeing a new Byfuglien we've never seen before, but do the numbers paint the same picture?

Bruce Fedyck-USA TODAY Sports

There has been a lot of talk in media lately around Winnipeg Jets defenseman extraordinaire, Dustin Byfuglien. Some individuals have tooted their own horns with "I told you so" in regards to Byfuglien the blueliner versus forward. Some have cited a new found dedication to defense and fitness by Dustin Byfuglien (ignoring that we've heard that story before).

Even Jets' own coach, Paul Maurice, has stated that the Byfuglien we are watching today is nothing like the one we've seen before.

As always, it is interesting to see whether the on-ice results match what is going around.

Byfuglien at forward and defense

Over the summer we compared and contrasted Dustin Byfuglien's performance as a forward. In the article we delved beyond the results and looked at the reasons why we see such a drastic distinction with microstatistics such as breakouts, zone entries, neutral zone play, and possession losses per puck possession. Here is the article if you wish to revisit it.

Some of course said, somewhat rightfully, that the 32 game sample size for Byfuglien as a forward was still small. Now we have an additional 26 games to compare. Here is Byfuglien for games as a forward versus games as a defenseman since the 2011-12 season.

Byfuglien (D) Byfuglien (F)
P/60 1.2 1.3
P/GP 0.37 0.29
SAC 52.3 49.0
relSAC +5.03 -2.65
SASC 51.6 48.8
relSASC +2.47 -4.95

The difference is quite stark.

Both Byfuglien the defender and forward score similarly per sixty minutes, but Byfuglien the defender scores more per game due to the added ice time. For added context, Byfuglien's defensive points per sixty is well above the 0.74 median for top pair defensemen, but as a defender he falls below the 1.5 median for third line forwards.

We then look at Corsi percentage adjusted for score (SAC) and see that the Jets are in the offensive zone more often with Byfuglien the defender, and are in the defensive zone more often as a forward. For added context, the median value for a first pair defenseman is 50.2, and 49.3 for a third line forward. The relative numbers show the Jets results in those statistics with Byfuglien on the ice versus on the bench, thus measuring Byfuglien's impact in those games.

Many cried out that Corsi overrated Byfuglien due its evaluation of all shots being equal (a straw man argument if Corsi is used as a proxy for puck possession). Recently though advances have allowed us to input many of the factors of shot quality into shot quantity models. War-on-ice has recently developed a score-adjusted scoring chance measure (SASC) that adjusts Corsi for shot location, rebounds, and the impact difference between shots off the rush and sustained pressure shots.

The added quality context seems to slightly improve upon player predictions for future goal differentials, although seems to be a wash with team predictions.

Those that screamed those claims should be happy that these measures show that Corsi may have been over exaggerating Byfuglien's impact as a defender. However, shot quality seems to indicate that Corsi over value both versions of Byfuglien equally. This makes some sense too when you think of Byfuglien's erratic defensive zone behaviour as a forward. Just as riveting of a discovery is the defenseman version still having a positive differential.

Old Byfuglien at Defense versus New Byfuglien at Defense

It's great and all to know Byfuglien is a better defender than forward, but what about the comments with his improvement? What validation do they have if any?

"Old" D Buff "New" D Buff
P/60 1.2 1.4
P/GP 0.37 0.43
SAC 52.1 54.0
relSAC +5.54 -2.52
SASC 51.3 54.3
relSASC +3.28 -9.15

When it comes to scoring, there seems to be a small difference in the two scoring rates which at this sample could be considered a wash (it's only a one point difference).

However, when we look at the two-way numbers like Corsi (SAC) and Scoring Chances (SASC), we see that some numbers are better while some are not. What's the deal with that?

The differentials seem to be better, while the relative numbers are worse. Why is that?

It's because the team as a whole is better. In theory, team strength in shot metrics should affect a player somewhat like this:


It passes the sniff test with logical thinking. For example, having better players on your team will likely improve your results but you won't be as good compared to the team any more.

Overall the Jets are a better team without Big Buff on the ice than previous seasons. Maurice has improved the Jets, as have the Jets with their buy-in on the Maurice's system. One of the largest impacts though has been the addition of #fancystats darling Mathieu Perreault, as well as the positive development of Mark Scheifele. While Jets always did well historically with Andrew Ladd, Bryan Little, Blake Wheeler, Tobias Enstrom, and Dustin Byfuglien on the ice, they now perform well without them as well.

In addition, Paul Maurice's system design accounts for pinching defensemen. Instead of shaking his head at risks being taking by the Jets very mobile defense core, Maurice has structured his forwards in order to turn this into a strength for the Jets. The Jets forwards cover for pinching defensemen.

While Byfuglien may very well have improved, the Jets roster being one step closer to that of a contending team likely holds a far larger impact.

Of course, there is also another factor: