Some players don't really play vs a certain throwing pitcher. For example,
Dave Roberts vs Righties? Noooo. Roberts hardly plays vs Righties
How a batter does vs a certain type of arm is only one of many stats I use in deciding whether or not to start him.
(another example, Jorge Posada vs Anyone? Nooooo. Posada hardly plays vs.... anyone..... )
"I'm going to meet the greatest umpire of all, and he knows I'm innocent."
-Shoeless Joe Jackson