Let me start off by getting something out of the way. I've only recently gotten into advanced statistics, but I think I know enough now to put this article together. If you see any misinterpretations or mistakes feel free to call me out.
When the Sens first acquired Matt Kassian I was not a fan of the move. I don't believe in dressing enforcers as in my opinion they make the fourth line essentially useless. Now don't get me wrong, Kassian hasn't lost the Senators any games and they haven't had any knockouts or Achilles tendon cuts since he's been in the lineup. However, from just watching the games it's clear Paul MacLean has not been able to rely on his fourth line as much as he has in the past. How Kassian has managed to not become a healthy scratch is beyond me, especially now that he's roughly averaging six minutes or less a game.
One advanced statistic that I've found interesting is WOWY (with or without you) which is able to measure how a player performs with or without another player. Kassian's primary linemates have been Erik Condra and Peter Regin. CF20 is the Corsi for per 20 minutes of ice time. Corsi is simply the total number of shots directed towards the opposition net (shots + missed shots + blocked shots). For this WOWY analysis, I chose the zone-start adjusted in close situations. In other words it ignores the first 10 seconds after a faceoff to negate the benefit of zone starts and only takes into account close play (when the game is tied or within a goal during the first and second or tied in the third). This is obviously the most important scenario, especially for the Senators with the majority of their games being close. With Kassian, Condra has managed a CF20 of 10.28 and Regin 10.24. However, away from Kassian, Condra has a CF20 of 22.90 and Regin 19.98. That means, playing with Kassian, Condra and Regin are only averaging 44.9% and 51.25% of the shots directed towards the opposition net when they play without him. Essentially their offensive output has been cut in half!
For a comparison let's take a look at Jim O'Brien's CF20 WOWY (with zone-start adjusted in close situations). With O'Brien, Condra has managed a CF20 of 22.04 and Regin 21.78. Without O'Brien, Condra has a CF20 of 20.61 and Regin 18.40. So both Condra and O'Brien direct more shots towards the opposition net with O'Brien than without him! In addition Condra and Regin are averaging 200.49% and 179.69% more shots with O'Brien compared to with Kassian. It's pretty clear that a fourth line of Regin-O'Brien-Condra is much more valuable to the team than Kassian-Regin-Condra in close games where every shot counts as a chance at taking the lead.
Furthermore, Kassian has one of the largest offensive zone starts percentages on the team (for obvious reasons) at 57.8%. However, he ends only 44.2% of them in the offensive zone. His linemates Condra and Regin start in the offensive zone 53.9% and 51.4% of the time, and end in the offensive zone 51.0% and 48.0% respectively. You also have to figure their numbers for percentage of time ending in the offensive zone have been skewed recently by playing with Kassian.
Taking into account Corsi relative (On-Ice Corsi minus Off-Ice Corsi, so essentially Corsi +/-), Kassian is well below Condra and Regin. You could probably conclude that he’s also dragged down their Corsi Relative based on the CF20 results.
> Condra 8.0
> Regin -0.7
> Kassian -3.8
Looking at their Relative Corsi Quality of Competition (the average Corsi relative of opposing players averaged by head-to-head ice time) Kassian by far plays the weakest competition. So knowing that, you would expect Regin and Condra to be able to produce more offence paired with him. However, the CF20 results previously mentioned don’t support that.
> Regin -0.275
> Condra -0.332
> Kassian -1.241
With the Sens currently on a 5 game losing skid and not being able to afford to throw away any more points you have to hope that Paul MacLean is finally considering making Kassian a healthy scratch. It's getting painful to watch the fourth line get thrown out there and have very little confidence in them getting a scoring opportunity, yet alone a goal. Fourth lines don't lose you games, but they do have the chance to win you them given the chance.
For reference, these are the two major advanced stat sites I used for this article: