On the “Energy Line” and Understanding Player Usage

^{Nichols note: The following is a post written by our newest contributor, @mannyelk. Give him a follow on Twitter.}

With the stinging pain of back-to-back losses in Alberta fresh in their minds, many fans have bemoaned head coach Paul Maclean's ice time allocation. "Interesting" is a euphemism I'd use to describe his TOI distribution in Wednesday's 4-1 loss to the Flames. Others chose to word it differently. The main source of fans' disdain is the healthy ice time total Maclean awarded the line of Greening, Smith and Neil. Indeed, a look at Ottawa's players sorted by TOI reveals that Smith received the third-most ice time among forwards while Clarke MacArthur, the team's fourth best scorer, had the least. In many ways, Wednesday's game was the culmination of a trend that's been active since the beginning of the season. 

For the most part, the tandem of Zack Smith and Chris Neil has been a constant since October. Neil's shared 81.7% of his time on ice with Smith. Colin Greening has split time between Smith's line and Spezza's, but seems to have settled into a left-wing spot alongside Smith in a more permanent fashion of late. The trio form the Senators' "energy line", a term I only ever use in jest. On the heels of a disappointing outing in which the line saw significant ice time, I decided to plot the trio's game-by-game TOI since the beginning of the season:

It's difficult to get a feel for the magnitude of TOI variance (which I'll get to shortly), but the chart plainly shows a marked increase in average ice time as the season's progressed. As is always the case with ice time allocation, this increase comes at the expense of other players; Clarke MacArthur and Bobby Ryan being the most recent victims. The latter recently remarked on coach Maclean's line juggling, causing a minor stir. Unbeknownst to Bobby, I'm sure, is that he actually benefits from the fifth-most consistent TOI distribution among Ottawa forwards. The player who ranks first in that regard is – you guessed it – Zack Smith. I used the standard deviation in players' game-by-game TOI to quantify this. Smith's 1.823 and Neil's 1.936 rank first and fourth on the team at the forward position. It's worth mentioning that MacArthur falls in the second-last spot ahead of only newly-departed Cory Conacher. 

In an effort to more fully understand Paul Maclean's player usage, I took a long hard look at the energy line's contribution to the team. I employed analytics to this end, exercising as much objectivity as I can muster. The truth is, I don't see the game through the same eyes as Maclean – And unless you've won a Jack Adams, odds are you don't either. As it happens, there's appreciable evidence supporting the theory that Ottawa's head coach is also a big proponent of analytics. Travis Yost has speculated quite a bit on the possibility. In the end, how much does it really matter? I don't believe it's unreasonable to expect the defending Jack Adams winner to make observations which mirror what the data tell us. 

This season I undertook a tracking project wherein I recorded zone entries and exits for the Ottawa Senators. Before I go any further, I'd recommend reading up on Eric Tulsky's work on the subject to anybody who hasn't already. What I found most intriguing about tracking zone entries was the potential to obtain another cool statistical by-product: zone time. By expanding the data set to include all entries and exits into and out of the zone and employing some crafty coding, one can extrapolate the time spent in-zone. I went and compiled on-ice 5v5 relative zonetime% for Ottawa players. I chose to express the rating as a percentage as it holds some familiarity to anybody who looks at CF% REL. It's essentially the ratio of offensive zone time for and against while a player's on the ice. Here it is plotted against deployment: 

Our "energy" players seem to fare rather well here. Between the three of them, they average ever so slightly positive despite D-zone heavy deployment. There's something to be said for a fourth line that can provide so-called "50-50 shifts" and maybe Maclean knows it. Granted, they typically don't face very tough competition, but they're not exactly top-end players themselves. Unfortunately, it's a dangerous practice to observe stats like these in a vacuum. You're taking an improper snapshot of a player's (or in this case, three) performance unless you use the right backdrop. The fact is, all three players are being significantly outshot while on the ice, and it's showing in the team's goal differential. What's causing this is shot density within the time spent in zone. It's the same phenomenon that makes Zibanejad a much better contributor than the graph above might indicate. Anybody familiar with the importance of zone entry data in hockey knows that not all entries are created equal. Those wherein the blue line is crossed with uninterrupted puck possession generate far more shot attempts on average than dump-ins. Over twice as many, in fact. However, they result in similar time spent in zone. This is the origin of offensive-zone shot density. The following chart (courtesy of Travis Yost) perfectly demonstrates what's ailing the Smith line: 

Those neutral zone scores are indicators that Greening, Smith and Neil are allowing far more clean zone entries against than they're creating for their team. My findings show that they rank dead-last on the team in their ability to enter the offensive zone with control; at a rate over 5% worse than the next Senator. While it's unfair to entirely discount the value of lengthy forechecking shifts, it's clear that our trio, as energetic as they are, concede offensive zone sequences of much greater quality to the opposition. By virtue of their ineptitude in the neutral zone, Smith's line routinely gifts the opposing team with advantageous territorial play. Therein lies the source of the trio's possession woes. 

Where does that leave us? While Smith and his linemates manage an acceptable ratio between time spent in either end, they can't manage shot density in the offensive zone great enough to offset what they allow. I don't mean to slight Maclean here, but it's easy to be fooled by puck-retrieval sequences. Hundreds of games worth of zone entry data don't exactly shine favourably upon dump-and-chase type players. To this observer, it certainly doesn't seem the energy line has earned its steady increase in ice-time. But, perhaps that's why I'm not a Jack Adams winning coach.