BSJ Analytics: Why did the Bruins want Nash (aging, questions) over Spooner (more points)?

Is Rick Nash really better than Ryan Spooner?

No, I'm not joking. Serious question.

I can hear it now: "Of course Nash is better! Nash is one of the top goal scorers of his generation, and has been a top 5 player in the league at various points in his career! Spooner is just a sheltered third liner who's a liability whenever he's on the ice! Idiot!"

I totally get it.

There's just one problem with this narrative: as I write this, Spooner has more points this year than Nash.

In fewer games.

With less ice time.

Spooner has 30 points in 41 games, and only 29 in 62 games for Nash. That's a difference of over a quarter more points per game. From that perspective, swapping out Spooner for Nash is not exactly a slam-dunk, home-run upgrade.

How can the public perception of these two players be so different from the story their raw point totals tell? Let's get the charts rolling to try and find out. Here's one showing the point production of each of them over the past few years.



We're using even-strength, points per 60 minutes of playing time here. Even strength only (for now) because how a player is used on the powerplay can affect their numbers almost as much, if not more so than, their actual talent. We'll look at "per 60" stats to try to remove ice time given as a factor. Finally, we'll look at both all points and just primary points. Primary points only include first assists and goals. We do this because secondary assists can be quite noisy, and a product of luck more so than skill. This is especially so on a year-to-year basis.

With that out of the way, you can see Nash recently peaked in the 2014-15 season, when he scored 42 goals in 79 games. Since then, however, his point production has declined pretty harshly. So to say that he's just having a “down year” right now is asinine. When an athlete is over 30 and has three “down years” in a row, it's not called a down year, it's called aging. There's a reason why the most common metaphor for an athlete aging is saying they “fall off a cliff." People don't talk about athletes “gently rolling down a gentle hill slope covered with soft flowers.” There's a cliff, and you can see right where Nash falls off of it in the chart above.

When you look at the gaps between their points and primary points this season, you can start to see where the difference in their point totals is coming from. Spooner has 20 even-strength points this season, for a P/60 of 2.63. But seven of his 20 5-on-5 points are secondary assists, the kind of noisy points that can inflate or deflate a player's stats. His primary points per 60 are only 1.71, almost a full point per 60 lower than his P/60 of 2.63. It's safe to say his stats at 5-on-5 have been inflated by secondary assists this year.

You really can't use these stats to say that either player is a better 5-on-5 point producer than the other. Looking at both players primary points per 60 over the past 3 seasons, it's been a bit of a toss-up between the two of them as to who scores better. Nash's production has slowed down, and so right now at 5-on-5 these two players are probably equals when it comes to 5-on-5 point production.

But, you see, there's a second part of each of these player's reputations, one that likely made the Bruins feel compelled to make this move. Nash is known as a quality defensive player and talented penalty killer. Spooner ... looks sort of like a cat chasing a laser pointer in the defensive zone.

I've got a chart for just this occasion. We'll look at Corsi rel and xG rel. Corsi is shot attempts. It’s the most predictive stat for future success, due to the giant sample size and low variance, and is often used as a proxy for possession. xG is similar to Corsi, but every shot is weighted by its likelihood to score a goal. Because you’re adding in more measurements, it’s less of a predictive stat and more of a descriptive stat. Finally, the "rel" suffix indicates how much of a difference your Corsi/xG was from your teammates. So if you have a Corsi Rel of 5%, your team controlled an extra 5% of shots when you were on the ice, and the same with xG.



That line at zero is pretty important. If you're above that line, that means you had a positive impact on your team's Corsi or xG. Below it, and that means you had a negative effect compared to your teammates.

Here's the biggest knock on Spooner's game. He's never been on the right side of that zero line, in either of these stats. It gets even more concerning when you look at his zone start stats. He has a ZSR of 75 percent this season, meaning that, of his non-neutral zone starts, he starts 75 percent of his shifts in the offensive zone. That's a giant number, with most players (including Nash) hovering around 50 percent. Spooner's been sheltered. This sheltering didn't really start until Cassidy took over as coach, which makes you question Spooner's uptick in rel Corsi, and especially rel xG.

Nash hasn't been outstanding by these metrics, but he's been above average and especially good this year. Nash clearly gives your team a better chance at controlling the puck when he's on the ice compared to Spooner. This is where Nash's value really comes in. I'm going to post stats for the Bruins' four most common lines this year, tell me if you notice something about Spooner's line.

[table id=27 /]

The Krejci/DeBrusk/Spooner line was easily the Bruins' worst line this year in terms of controlling the puck, despite starting a crazy amount of their shifts in the offensive zone. They started less than a quarter of their shifts in the defensive zone, yet weren't above water in terms of rel Corsi and were pretty heavily below water on rel xG.

Nash isn't a better scorer than Spooner. But that's not what the Bruins' second line needs. Nash is a much better puck possession player than Spooner. But he's much better at driving play and helping his team control the puck. And that is what the Bruins' second line desperately needed. If this team did have a hole coming into the trade deadline, it was the play of that second line when they didn't have the puck. Nash upgrades that, and that's not debatable. Whether that upgrade was worth giving up a first-round pick and Ryan Lindgren, I'll let you decide.