Every team has them. Some teams have more than one. That player who has either exceeded expectations, has fallen short of those goals or seems on the verge of something but you're just not sure how it will turn out.
So who are these players? And how important will they be to their teams going forward? Well, that depends upon the player, the team and their current situation.
Here's a look at a key player to watch for every team and the potential impact they could have on their clubs.
How we rank: A panel of ESPN hockey commentators, analysts, reporters and editors rates teams against one another -- taking into account game results, injuries and upcoming schedule -- and those results are tabulated to produce the list featured here.