are right handed batters better against left handed pitchers
Conventional baseball wisdom suggests that, when a pitcher and a hitter pitch or bat with the same hand, the pitcher typically has the advantage. This especially holds true for left-handed pitchers, as lefties are less common in a major-league lineup than righties. As a result, the most common use of the lefty-righty switch is when a right-handed pitcher is facing a left-handed batter. The manager of the defensive team will sometimes go to the bullpen, especially in close games where a reliever has already entered the game, and pull out a left-handed specialist to face the left-handed batter. The new pitcher will then attempt to get the batter out. Whether he succeeds or fails, the pitcher will often be replaced after the at-bat.
Lefty-righty switch