In competitive events the more experience you have against a particular opponent means the more information they have about how you play and vis versa. As this knowledge increases certain tools become more and less valuable.

For example, consider facing a knuckleball pitcher in baseball. Knowing they will throw knuckleballs a majority of the time and not being as familiar with their release motion means sneaking a fastball in can really catch you off guard. Then, as you learn how these pitches look the unexpected fastball becomes more predictable and, therefore, less valuable.

Does the data support this theory?

Sort of – it depends on the pitchers. Here are the pitches thrown to players based on how many pitches total they threw to that batter for pitchers that had notable results:

To get this data I took information from PITCHf/x from Brooks Baseball and then used pandas in python to form the graphs. Here is the source code to check out other players

Do you have any insight as to why some pitches scale better? Let me know in the comments below