Baseball has always been a game where the players police each other.
If a teammate gets hit by a pitch seemingly on purpose, an opponent's player will get hit sometime in the near future.
There are also other unwritten rules that apply, such as don't slide with spikes up, don't run across the pitcher's mound after an at bat and many others.
Just because a player doesn't follow all of these rules doesn't necessarily make them dirty. What does make them dirty is the fact it has happened on multiple occasions.
The following are the seven dirtiest players in the game today.