Looking at early data from statcorner, both Perez and Castro exit the opening series a negative. The data is umpire dependent and is good for comparison within a game or series early on but not across the league. In this series, Castro came out a -9 and Perez -16 (out of zone strikes - in zone balls). Castro gave the Twins an edge in this series. To illustrate the umpires influence, you will see that two of the top three on the plus side came from the same series. I am not arguing that the data isn't meaningful. While umpire dependent, the sample becomes large and the umpires vary widely reasonably quickly. Castro won the battle in the first series. Let's hope he wins more of these battles.