Felix Hernandez and His Fastball, Part 2

Today, moving on from yesterday where we looked how Felix’s overall fastball percentage moved as the game wore on. This time, I drop the overall view and instead treat each pitch number separately to get a sense of when (besides early in the game) that Felix dials up the heater. Included in this graph is a red bar marking his overall average for all pitches and a rolling 5-pitch average to give you a more smoothed sense of the trend.

We see that Felix reaches his overall average at about the 20-pitch mark into a game and then hovers around that mark for the remainder of the start, with some obvious variation. It is still a clear downward trend over time.

I decided to zoom in on those first 20 pitches, where Felix throws a fastball just under 80% of the time. Take a breath and soak that in first; on average, 16 of the first 20 pitches that Hernandez offers at the beginning of a game are a fastball. That’s predictability to an extreme and if I can spot it, you better be sure that opposing advanced scouts can spot it.

Here I made a time line of Felix’s 2008 season and in blue you will see the percentage of fastballs thrown in the first 20 pitches for each start. Again the horizontal red line marks Felix’s overall fastball ratio and I have included a horizontal green line to mark Felix’s average fastball ratio amongst this sample.

Next time, I will take a look at the games where Felix does exhibit some differences in pitch selection at the onset.

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Matthew Carruth is a software engineer who has been fascinated with baseball statistics since age five. When not dissecting baseball, he is watching hockey or playing soccer.