Last season, when the Chicago Blackhawks beat the Vancouver Canucks in six games, Chicago's depth advantage was seen as the key factor in its success. Beyond top stars like Patrick Kane, Jonathan Toews, Patrick Sharp and Marian Hossa, the eventual Stanley Cup champions were stacked with a huge arsenal of secondary talent including Dave Bolland, Dustin Byfuglien, Kris Versteeg, Troy Brouwer, Andrew Ladd, Tomas Kopecky and more. Throughout the 2009-10 regular season, Chicago enjoyed a league-leading 49.2 goals of value above replacement-level from its third- and fourth-line players.
Consider last year's playoff matchup between Chicago and Vancouver:
While no one questioned that Vancouver's top-shelf players Henrik and Daniel Sedin, Ryan Kesler, Alex Burrows and Mikael Samuelsson could match the Hawks, the Canucks could ice only a handful of decent secondary talents, such as Kyle Wellwood, Pavol Demitra, Steve Bernier and Jannik Hansen. Unfortunately for Vancouver, even those select few proved no match for Chicago's third-liners. As a percentage, the Canucks' depth players were responsible for only 16.7 percent of the team's non-goalie Goals Versus Threshold (GVT), the Hockey Prospectus metric that evaluates player value. That figure is the lowest among teams that made the postseason.
History is therefore not telling us that depth is a bad thing, but rather that it is far less important than how good the team is overall, regardless of where its goals come from.
When watching that series, it certainly appeared that having a deep roster is one of the keys to going far in the long and physical postseason, and that relying too much on your top line is a recipe for an early exit. That may have been true in this particular case, but the data show that this is far from the rule. In fact, teams from the 2009-10 season whose depth players represented the larger percentage of team GVT were actually more likely to lose.