The Tampa Bay Lightning are a very good hockey team. In fact, they’re one of the best teams in the NHL this season. They have the most standings points by a comfortable margin. They lead the league in goal differential, also by comfortable margin. They are second in the league in 5v5 expected goal share. By any reasonable method of ranking NHL teams, the Lightning are near the top.
Whenever a team is playing as well as the Lightning are, the discussion in the media will always turn to depth. Saying that Steven Stamkos, Nikita Kucherov, and Victor Hedman are good players starts to sound like thin analysis. To find something new to say, pundits will start to laud the bottom six forwards and the bottom pair defenders.
At face value, the importance of depth seems obvious. But Alex Novet’s work on hockey being a strong link game suggests that the narratives around depth are overwrought. He found that having the best players at the top of the roster is more important than having strong play from depth players. If we want to understand which teams are likely to be successful, we’re better off examining the top of the roster than the bottom.
In that respect, the Lightning are right where you’d expect to find them. Over the last two seasons, they have six players in the top 50 players according to Wins Above Replacement (WAR) from Evolving Hockey. That’s twice as many as any other team. The top of the roster is stacked. That shouldn’t be a surprise.
But, what about depth? We know it isn’t as important as the top of the roster but trying to measure it could still be a fun bit of trivia.
To the eye, the Lightning are a deep team. They have so many good players this season that they can’t find minutes for them all. A fully healthy Lightning team will be benching Adam Erne and one of Erik Cernak, Braydon Coburn, or Mikhail Sergachev on the blue line. Erne would be playing on most teams’ third lines. Cernak and Sergachev deserve to be getting second pair minutes, and Coburn is a borderline fourth or fifth defender based on his performance this season.
That sounds like a lot of depth. But is it a lot of depth? There are plenty of interesting ways to try to answer this question. Travis Yost measured what might be the inverse of depth when he looked at the most top heavy teams by measuring the percentage of goals scored by players on the top line or the top six. Using that approach, the Lightning look fairly top heavy. They weren’t particularly reliant on their top line, but the top six was doing most of the heavy lifting in terms of scoring at that time.
Yost’s approach is a good one, but I decided to try something different. Using WAR from Evolving Hockey, we can count how many players on the roster are at or above replacement level and how many are below. Think of replacement level as the typical 13th forward or 7th defender on an NHL roster. They are an NHL player but could be replaced by a call-up from the AHL with little or no impact.
For this exercise, we’ll focus on the top 13 forwards and 7 defenders in minutes played for all NHL teams going back to 2007-2008. That gives us 620 team seasons. By this definition, maximum depth would be having all 20 players at or above replacement level, while minimum depth would be to have all 20 players below replacement level.
The first chart shows all 31 NHL teams this season. The blue blocks are forwards and the orange blocks are defenders. A block above zero indicates a player above replacement level and a block below zero is a player below replacement level.
So far this season, the Lightning have all 20 of their top skaters in minutes played at or above replacement level. The Predators are second with only two skaters below replacement level. The Canucks and Ducks tied for last with nine players below replacement level. To clarify, that means those teams have rosters where nearly half of their regular players are below replacement level. Not good!
While this chart tells us the Lightning are the deepest team so far this season, it doesn’t give us much context for how to interpret that. To understand what this means, we need to see how often this happens. If it happens every year, then maybe it isn’t so meaningful. If it never happens, then maybe we should pay attention.
The chart below is a histogram that shows how frequently teams have had a given number of players above replacement level.
The most common roster construction in the data set is 15 players at or above replacement level and 5 below. While what the Lightning are doing so far this season isn’t unprecedented, it is rare. Only two teams prior to this season have been this deep. The 13-14 Blues and the 17-18 Jets both had zero players below replacement level.
This year’s Canucks and Ducks, while bad, aren’t doing anything particularly novel. If you’re wondering who the team that managed to ice 12 below replacement players was, it was of course, the 13-14 Sabres.
We’re not yet halfway through the season so things could change for the Lightning through the winter and spring. But to this point, they’re showing the type of depth that only a couple of teams in this era have been able to put together. That’s a credit to the front office.
Hockey is a strong link game. The Lightning’s strong links are as strong as any team’s. They’ve managed to supplement those strong links with a roster that lacks any significant weak links. That bodes well for their chances this season. With the cap crunch coming next summer, this might be a unique opportunity for this group to make a run without any obvious gaps in the roster.