# Pitch Values, Pitch Types and Counts

#### Introduction

A few weeks ago, I reviewed the concept of pitch value and showed smoothed graphs of pitch value for different pitch types (four-seamers, sliders, and changeups) over the zone. One key thing that I ignored was the role of count in the choice of pitch type. For example, pitchers will typically throw a fastball on the first pitch (0-0 count) and throw an off-speed pitch when they are ahead in the count. Recently I’ve added some functions to my CalledStrike package that compute pitch values and make it easy to graph pitch values over the zone. This package includes a Shiny function `PitchValue()` that uses 2019 data to select a pitch type, a batting side and pitch side and displays the smoothed pitch values across a group of counts. Here I will use these displays to show how the value of a specific type of pitch can dramatically change across counts.

By the way, my Analyzing Baseball with R coauthor Max posted on this same subject in a Hardball Times post. A current introduction to many of the functions in the CalledStrike package can be found here.

#### Values of Four Seamers

To begin, suppose we want to explore the pitch values of four-seamers (pitch type FF) across all 1 and 2 ball counts. Here I am focusing on right-handed pitchers to right-handed hitters, although it is easy to consider other matchups. Recall from my recent post that larger pitch values (orange color) are beneficial to the pitcher and negative pitch values (yellow towards blue) are beneficial to the hitter. What do we see below?

• Generally it is desirable to throw a four-seamer high or outside to a right-handed hitter.
• For 0-strike counts (1-0 or 2-0) the pitcher wants to locate the pitch within the zone.
• As the number of strikes increases, it is desirable to locate somewhat outside of the zone. Note that there is a sizable orange area outside of the zone for the two-strike counts 1-2 and 2-2 — these correspond to swing and misses on these pitches out of the zone.

#### Values of Change-Ups

The count has a different effect on the value of off-speed pitches. To illustrate, here are graphs of the values of change-ups (pitch type CH) on one and two ball counts.

• On 0-strike counts, the pitcher gets positive value from change-ups thrown in the middle of the zone.
• On 2-strike counts, it is now desirable to throw change-ups low outside of the zone.
• On a 1-2 count, note the green area inside the zone — this is a poorly placed changeup which tends to be put in play for a hit.

#### Values of Sliders

Sliders (pitch type of SL) have a similar pattern to changeups.

• On a 1-0 count, pitcher wants to throw a slider on the outer side of the zone, and on a 2-0 pitch, any slider in the zone will be good.
• On one-strike counts, it is now advantageous to throw the slider outside, even outside of the zone. There is some advantage in throwing high-inside on a 2-1 count
• On two-strike counts, the pitcher really wants to throw his slider low-outside or high-inside, preferably outside of the zone. Again, note the sizeable regions of yellow in the middle of the zone for the two-strike counts — these correspond to the hanging sliders that are put in play for hits.

#### Summary Pitch Values of Pitch Types

We know that specific counts like 1-2 and 0-2 favor the pitcher and counts like 2-0 and 3-0 favor the hitter. But do these advantages carry over to specific pitch types? I have a dataset that provides pitch values for all pitches for the 2019 season and it is straightforward to find mean pitch values for each pitch type and count.

Below I graphically compare the values of four-seamers (FF) with the values of change-ups (CH). I’m graphing the mean pitch value as a function of the pitch number where I use the count as a label. Note that the mean pitch value of a fastball (left panel) is positive for the neutral and hitter counts, and negative for the two-strike counts favoring the hitter. For change-ups (right panel) we see an opposite pattern — the mean value of a change-up is positive for two-strike counts and negative for the neutral and hitter counts. (Due to the large negative mean values, pitchers should not throw change-ups on 3-0 and 3-1 counts.)

Here is a similar comparison of four-seamers (FF) and sliders (SL). Note that sliders tend to have positive values for essentially all counts (except 3-0). Sliders are especially valuable for two-strike counts (0-2, 1-2, 2-2, 3-2) and even 2-0 and 3-1 counts. This tells me that pitchers likely are throwing their sliders low and outside, the regions where we saw they had positive pitch values.

#### Shiny App

If you install my `CalledStrike` package, you can load the package and run my pitch value graphing Shiny app by typing

```library(CalledStrike)
PitchValue()
```

Here’s a snapshot of the Shiny app where I am looking at the pitch values of southpaws against right-handed hitters for curve balls (CU) on the 0-0, 0-1, 0-2, 1-0 counts. A middle-of-the-zone curve ball on a 0-0 or 1-0 count is fine, but a middle-of-the-zone curve ball on a 0-2 count will be disastrous for the pitcher.