Baseball strikeouts analysis

In my last story on a time series of strikeouts in baseball, I noted that one potential explanatory factor for the increase in strikeouts over time is the introduction of specialty pitchers. The hypothesis is that tired starters are being removed earlier in games and fresh relief arms brought into games. I threatened another post to consider this hypothesis, and here it is!

First, for this analysis, the summary-level MLB data won’t suffice, as we will want to look at strikeouts by inning (rather then just in aggregate) to determine: