Which position is the most important in a playoff series?

I picked goalie, but there are two I think could be in the discussion.

A dominant nose tackle - If you have a guy over center who just cannot be blocked by one or two guys, but you need to devote three players to that person, you have an amazing advantage. For example, the Steel Curtain would have been nothing more than a good defense without Joe Greene.

I will take crap for this, but IMHO, the most important position in any team sport is a softball pitcher. I know it is not on the list, but you can ride a dominant pitcher for an entire game, series and season.