What is Pitch Run Value?

Marlins' SP Sandy Alcantara; Photo via Ryan Casey Aguinaldo

In the current sabermetric era, there are hundreds of advanced stats, and new ones are seemingly created every week. To most fans, these metrics seem useless and unimportant. However, there are some advanced stats that can help common fans understand more about what is happening during a game. One of these stats is Run Value on certain pitches. Once explained, this is an easily understandable metric that is great for evaluating both pitchers and hitters.

What is Run Value?

Run value is a stat that has been popularized by Baseball Savant, as it is one of their baseline metrics and is easily accessible on their website. To understand Run Value, it is first important to understand Run Expectancy and Win Expectancy. Every pitch thrown in a baseball game affects the probability of either team winning and the number of runs scored in a game. This can be in a big way or a really small way. Run Expectancy will be highlighted because it is central to Run Value. To first understand run expectancy, it is important to understand the Run Expectancy Matrix.

The matrix above is the number of runs a team is expected to score in each given scenario. With 1 out and a runner on first, a team is expected to score 0.489 runs. With no outs, their scoring jumps to 0.831 runs. However, Run Value is derived from Run Expectancy on a pitch-by-pitch basis, shown in the graph below.

Situation	wOBA	WRAA/PA	Value of Strike	Value of Ball
3-0	0.622	0.239	-0.117	0.051
3-1​	0.470	0.123	-0.066	0.168
2-0	0.436	0.097	-0.062	0.143
3-2	0.384	0.057	-0.294	0.234
1-0	0.355	0.035​	-0.035	0.088
2-1	0.352	0.032	-0.069	0.064
0-0	0.310	0.000	-0.037	0.032
1-1	0.293	-0.013	-0.054	0.048
2-2	0.273	-0.028	-0.209	0.085
0-1	0.262	-0.037	-0.051	0.024
1-2	0.223	-0.067	-0.171	0.038
0-2	0.196	-0.087	-0.150	0.021

There is a lot of information on that graph, but it can be simplified. Above is each count and the wOBA, wRAA (weighted runs above average), strike value, and ball value of that count. Now the two most important metrics are Strike Value and Ball Value. Every pitch a pitcher throws in an inning will increase or decrease the odds of the opposing team scoring a run in that inning. Negative Run Values signify the offense consistently having a worse chance to score due to a player’s play. If a pitcher is the result of a sluggish offense, that is great. If a hitter is responsible, that is bad. To quickly understand how this works, let’s look at an at-bat with no runners on base.

Count	Result	Value of Pitch
0-0	Strike	-0.037
0-1	Ball	0.024
1-1	Strike	-0.054
1-2	Strike	-0.038

Throughout this at bat the pitcher hurt the other team's chances of scoring by -.105 runs (the sum of all the pitch values). Now you still have to account for balls in play. In the interest of not littering this article with graphs, the Run Values for balls in play can be found here.

To sum it all up, every pitch thrown in a baseball game has a value attached to it based on how it affects the offense's ability to score runs. To calculate Run Value, all of these small little totals are added up throughout the game. Every pitcher and hitter is assigned a Run Value, which accumulates throughout the season.

The best way to use all of this data is to examine the effectiveness of each pitch in a pitcher's arsenal and to judge how good each hitter is against each type of pitch. For example, if, throughout a game, a pitcher compiles a -2 Run Value on his fastball but a +1 Run Value on his slider, then his fastball is his superior pitch. If a hitter accumulated a +1 run value against cutters and -3 against curveballs over a 5-game span, he was much better at hitting cutters over that span. This can become a really easy and simple method to examine a pitcher's pitch and how good a hitter is versus a certain pitch.

When looking at run value, it is important to understand a couple of things, mainly that it is not an end-all-be-all stat. For example, a hitter could get a couple of lucky hits against a pitch, propping up his Run Value way higher than it should be. The same can be said for a pitcher, as he can get outs on pitches that were mistakes, artificially deflating his Run Value. It is also important to look at sample size. How often a pitcher throws a pitch and how often a hitter sees a pitch can influence run value as well, and each of those sample sizes needs to be sufficiently large to draw meaningful conclusions.

Run value is an extremely important stat in today's game, as it gives managers and coaches more valuable information and data to use. If there's a guy at the plate with a -6 run value (he produces negative value as a hitter) vs sliders and a Manager has a reliever with a -4 run value (he produces a positive run value as a pitcher) on his slider, it is an easy decision to bring him in to pitch. Run Value can also help fans better understand the game and gain a more insightful perspective of what is happening on the field. Next time you catch yourself at a game or watching one on TV, take a quick trip to Baseball Savant and look at some pitch's run values to help understand this beautiful game more.

Sources:

BaseballSavant.com

DRaysBay.com

"Sandy Alcantara 8.11.21" via Ryan Casey Aguinaldo licensed under CC BY-SA 4.0