A hot goaltender can change the complexion of a series or even of an entire postseason. Top seeds can be upset, with underdogs advancing deep into the playoffs, as when Jaroslav Halak and the eighth-seeded Canadiens upset the Capitals and Penguins in 2010. And a netminder having a season -- and postseason -- for the ages can carry a good team to the grail that is the Stanley Cup, as Conn Smythe winner Tim Thomas did for the Bruins in 2011.
Before each of the past three playoffs, Hockey Prospectus and Insider set out to forecast goaltender performance, as measured by save percentage. Halak and Thomas were our second- and first-rated netminders the past two postseasons, so we've fared pretty well.
That said, goaltender performance can vary greatly in the small sample size of a short playoff run. In fact, we've seen how performances can vary greatly even from season to season with recent examples like Brian Elliott and Mike Smith. We do our best to predict which netminders may succeed or fail, with indicators like career playoff save percentage (modified this postseason to include only data from 2005-06 forward), current regular-season save percentage and current regular-season shots on goal against. Here's how the 2012 playoff field breaks down.