I've been following the NHL for two years but I never really understood goalies.
Last night, we had Ryan Miller taking the goaltending position in the third period. But we don't always have a goalie sitting at the back waiting to be summoned do we? Even when we were giving up 6 goals in the New Year's Game against the Bruins. Miller was never taken out. (Maybe it was because Lalime pales in comparison to Miller?)
So what determines that a goalie can take the place of another during a game? Does NHL have rules on that? Or is it really based on economical reasons? Paying for two players instead of one? Because I have seen other teams do that when they are down by goals.