One of the most important characteristics for any baseball player to have is that intestinal fortitude"—the ability to play at 100 percent all the time. Having this trait means the player will hustle, do the right things both on and off the field and will want to be in the game helping his team anyway he can.
From time-to-time, the media will say a particular player is a great "clubhouse" guy, which, to me, is one of the most important characteristics for a baseball player to have. Someone like this can pull a clubhouse together and gives a leader for the rest of the guys to follow. Often, this player is either the star of the team or, even more often, an older veteran who's role on the field has been diminished to coming off the bench. A great example of this would be Alex Cora.
This article looks to find a player on each team that embodies both of these important characteristics; that is to say the player is consistently playing hard and is a leader in the clubhouse.