Keep rolling, rolling, rolling those lines: Part 1

Over the years, many have praised the Bruin's ability to "roll 4 lines". It's gotten to the point where the praise is just slightly ridiculous. Let's examine this Chris Kelly quote that came after a 2-1 win against Arizona in 2014:

"That's our strength, our depth and our ability to roll four lines," Chris Kelly said. "I think a perfect example was the last game where we were able to roll four lines the whole time and I don't know if Phoenix did." - per Metro West Daily News

Now, there's depth, there's wanting everyone on the roster to contribute, and there's what the Bruins used to do. In Claude Julien's old system, "rolling 4 lines" meant EVERY line played in EVERY situation. Down a goal, there's 5 minutes left in the third, and the other team's worst line has just iced the puck? Play Campbell! Up a goal with 5 minutes left, defensive zone face off, against the Malkin-Crosby line? Put out Seguin, and if he screws up we trade him! ALL SITUATIONS, GUISE.

But if you've been watching the Bruins over the last couple seasons, you may have noticed that Claude seems to have thrown that strategy straight out the window. It seemed to start with Torey Krug. For a while Krug and whoever his partner happened to be at the time were the only players allowed to start +40% of their shifts in the offensive zone. The next big change came from the addition of David Pastrnak and Ryan Spooner. In 2014-15, David Pastrnak started more shifts in the offensive zone than any other player with over 300 minutes. The Lucic-Spooner-Pastrnak combo just flat out didn't play good defense, and still managed to get ice time.

This wasn't just one line getting more offensive starts. There was an appreciable spread in the way lines were used. Despite the next day rants and photoshops from DoY, even the Bidet himself was subject to this trend. Per war-on-ice, in the lockout shortened 2012-13 season, Gregory Campbell started 5.65% less of his shifts in the offensive zone compared to the average Bruin. In 2013-14, it was 7.04% less. And last year? 11.45% less.

This stratification isn't limited to the Bruins. It's been a league wide phenomena that the Bruins are quickly catching up to. Per stats.hockeyanalysis.com, here's the offensive zone start standard deviation for the Bruins and the rest of the league over the past few seasons, minus the lockout shortened 2013 season.

And here's the standard deviation for all teams in the 2014-15 season.

It's also worth noting that the standard deviation of all player's zone starts has been rising steadily as well. That's because, well, the strategy Claude's implementing works well. Chicago and Nashville are probably the two best examples of this system working wonders. To be fair, a part of it is the players you have at your disposal. You try having Marcus Kruger or Paul Gaustad on your team and not deploying them in every defensive zone start! But coaches and GMs are a team, and a GM will certainly prefer players who fit their coaches system.

In part two, we'll look at just how successful this strategy has been and can be.