Good question. The rules of baseball do not allow errors to be charged against pitchers and catchers when pitches are delivered because of the number of times they handle the ball in the course of a game. However, when a pitcher delivers a pitch that the catcher cannot handle with ordinary effort, pitcher is charged with a wild pitch (WP). When the catcher cannot handle a pitch that should have been caught with ordinary effort, he is charged with a passed ball.
When determining earned runs, passed balls are treated as errors. However, wild pitches are not treated as errors. The reason is that the pitcher was responsible for the batter reaching 1B on DTS-Wild Pitch(catcher could not handle pitch with ordinary effort).
Hope this is clear as mud.
