One of the worst realizations in fantasy is finding out that managers and general managers don't give a flying poo about your fantasy roster. They'll bench a dude who's mashing the ball if his defense is sub-par or send someone to the minors to work on playing a position that many view as unrealistic. I understand it, but that doesn't mean I have to like it.
Some of the guys below have been victims of this management. That makes them a bit risky as investments, but it doesn't limit the upside they have when they do play.
As a note, I generally limit this list to players who are owned in around one third or fewer of ESPN leagues.