Word came from the Oilers yesterday that Ales Hemsky has a torn labrum and is going to be undergoing surgery on his shoulder and will miss five to six months which means he should be back in time for the playoffs. Sorry. Black humour. The straw that broke the camel's back was a hit by Michal Handzus in the game a couple of nights ago against Los Angeles but both Ales Hemsky and Steve Tambellini made it clear that the problem had been ongoing and the problem needed to be fixed regardless. The general mood around the team is that this is it, the Oilers are done and heading for the lottery. After all, Hemsky really is capable of playing tough minutes to a draw or better more often than not, he's the team's best offensive player and the key cog on the power play. Saying the impact will be "big" seems like an understatement. In order to get a better idea of what impact this injury might have on the team going forward I decided to use a method called "With of Without You" which will look at the team's goal differential when Hemsky has been in the lineup and when Hemsky has been out of the lineup over the last four seasons. I would have preferred to use shots on goal with the score tied but didn't have the data at hand. The results after the jump.
I was introduced to this method by a Gabe Desjardins article on Saku Koivu and he was introduced to the method by Tom Tango (who used the method in his work on baseball). Thanks very much to both of them. Anyway, back to Hemsky. These results are for the 2006-07 season through the 2008-09 season so far. I decided not to use data from the 2005-06 season because (1) Hemsky played in 81 of the games that year and (2) that team was significantly better than the teams that followed it and I thought including that season would unfairly juice Hemsky's numbers. The analysis would be helped with a few more games of Hemsky out of the lineup but, as an Oiler fan, I'm not about to get too upset at Hemsky for being too durable. All of the goal differential numbers do not include shootout goals. So here's the data:
When I first looked at the "With Hemsky" numbers I was shocked at how bad they were. I was then heartened somewhat after looking at the "Without Hemsky" numbers. It's not Hemsky that's bad, it's the Oilers! It turns out that without Hemsky in the lineup both teams score less. In the case of the opposition, they score a bit less while the Oilers score a lot less. This wasn't true to form yesterday but it seems that for the rest of the year Oiler fans can look forward to lower-scoring hockey games.
Edit Alert: I edited this paragraph extensively after Tyler Dellow made some corrections to my math in the comments. As for Hemsky's impact, it's pretty large, namely
0.15 0.25 goal differential per game. That would put Hemsky's contribution over the Oilers replacement for him at 12.3 20.5 goal differential over an 82 game season. If we assume that 3 6 goal differential is equal to about one win that puts Hemsky's contribution to the team at about 4.0 3.4 wins or 8.0 7.2 points above his replacements. That is an enormous difference, much more than I would have guessed. Let the death march continue.