So on Thursday, I went on a bit of a rant about the role of defensemen in the NHL. Well, rant is probably the wrong word, as it wasn’t particularly emotional, so let’s call it instead a “tweetstorm”. This piece will expound upon those tweets in greater depth, as I think it’s a topic that deserves a little more than what 140 characters and snark can provide.

Though I can’t promise this won’t also include some snark.

The entire discussion was kick started by this tweet:

Now, you’re probably thinking “oh man, a Shea Weber analytics take. Let me go get my popcorn for the inevitable scathing fallout.”

Sorry to disappoint, my friend. I like Shea Weber.

I don’t like the Weber-Subban trade for Montreal, but I have no particular issue with Weber’s game, especially throughout the first part of this season, when he’s been very good. I rather doubt he’ll stay the top guy when we check in at around 40 games or 60 games, but for these first ~23 games, sure. Pencil him in for your vote.

What I do have an issue with is how low Brent Burns is ranked in those votes. More to the point, I have a major issue with this:

This is where the whole thing goes a bit off the rails.

Marc-Edouard Vlasic is a very good defenseman. He’s smart in the defensive zone, stacks up well against tough competition, and even had himself a career year in points last season.

But if you have to have one guy playing the most minutes for your team’s defensive corps?

You need to pick Brent Burns every time.

This quote (and my reaction) illustrates the one biggest question remaining around the evaluation of defenders.

What exactly are they supposed to be doing?

Do defenders:

A. Prevent goals?

Or

B. Drive play forward?

“A” seems obvious to traditionalists. It is right there in the name! Defenders play defense.

Defenders are supposed to protect the goalie. Supposed to block shots. Go into the corners. Level crushing hits. Get in shooting lanes.

And do all of this in the D-zone.

At the opposition’s blue line, they need to be careful. Pinch too aggressively and you can allow a breakaway. Don’t make the risky play – let the forwards do that. After all, they’re the guys who are tasked with getting the puck to the net.

This is the kind of hockey that worked for years. The years in which many of today’s pundits actually played in the NHL.

And it’s the kind of hockey that is incentivized by the current point structure.

Currently, teams are rewarded for “not losing”, aka preventing goals against.

This can make defenders who play a conservative game look like they are helping their team win more games.

But Not Losing isn’t the same as Winning.

To win games, you need to score goals. Preferably lots of them.

To score goals you need to be in the offensive zone, which is why I — and most analytically inclined people — prefer option “B” out of a defender. That is, we want them to drive the play forward.

First and foremost, getting the puck into the offensive zone is a skill. With more and more emphasis being placed on neutral zone play, a defender who is good at zone exits and assisting on zone entries becomes worth their weight in gold.

While things like hits are easy to point at and say “look, he’s defending,” the plays that start a breakout are often subtler. Anyone can block shots, but not everyone can repeatedly make crisp tape-to-tape passes across the neutral zone.

But not only does driving play forward mean you have a greater opportunity of scoring goals, it also means that you’re spending less time in the defensive zone. You are, in effect, preventing goals against.

The “transition game”, as it’s commonly referred to, is the next wave of NHL defense.

It’s how the Penguins were so dangerous last year. It’s even how the L.A. Kings, Corsi darlings, prefer to play. The Kings aren’t what anyone would call a fast team, but they corral pucks quickly and move them up ice with efficiency.

Teams that opt to play a “defense first” strategy, like last season’s New Jersey Devils, are often pinned in the D-zone for long stretches of time, which limits offensive abilities.

Now, most people come back and say “I want option C – both!”

Well, me too, but let’s wish in one hand and spit in the other and see which fills up first.

That’s not to say there aren’t defenders out there who can both drive play forward and look like they’re playing conservatively in the d-zone. In fact, you can make an argument that Weber in Montreal is doing just that.

But they are rare, and most players tend to skew one way or another. Beyond that, most coaching systems tend to prefer one of the two also, so even if you have that good “200-foot guy”, he’s going to play the way his coach wants.

In the end, I think we can all agree on one thing – evaluating defenders is hard.

This is why analysts prefer statistics, though. Because the numbers give us something concrete to base our assumptions on. And right now, a transition-focused defense is more valuable than a traditional “stay-at-home” one.