The Controversy

Umpires & Referees. They are a part of nearly every professional sport. They have the biggest influence on the game besides the athletes who are competing (of course).

What if we could get rid of the umpire influence in baseball?

I'm sure baseball fans have yelled at the umpire through the TV multiple times saying "Hey Blue! That pitch was way outside!" Occasionally, the baseball fan might be biased and want a 50/50 call to go their team's way. However, there have been countless situations where the umpire has blown a pitch call which played a significant role in dictating the outcome of the game.

Let's take a look at a pitch from game 1 of the recent 2018 World Series:

It's game 1 of the World Series, according to sabr.org, the team that wins the 1st game goes on to win the World Series 64% of the time. The stakes are VERY high, to say the least.

So it's a tie game 2-2 heading into the bottom of the 3rd. Tim Timmons, the home-plate umpire, does a great job of pitch calling in this at bat until the 1-1 count. The 1-1 pitch is a curveball that, according to the pitch by pitch data, clips the top of the strike zone:

Pitch by pitch data is pulled & modified from baseballsavant.com

Let me put these data points into English.

Plate_X is the horizontal placement of the ball. The value of the leftmost plate_x value of a pitch that's in the strike zone is -0.833 ft & the rightmost is 0.833ft which adds up to 1.66 ft of horizontality in the strike zone. According to the MLB rule book, in order to get a strike call, part of the ball must cross over part of home plate. Let's assume part of the ball means at-least half of the baseball. Home plate is 17 inches long. Adding half a ball's length to both sides of the plate gives us a total of 19.94 inches which is also approximately 1.66 ft.

Kershaw's 1-1 curveball was given a plate_x value of 0.8027. This value is greater than -0.833 (leftmost limit of strike zone) and less than 0.833 (rightmost limit of strike zone). So, the pitch was delivered within the strike zone horizontally.

Here's an excerpt from the MLB Rulebook:

"The area over home-plate the upper limit of which is a horizontal line at the midpoint between the top of the shoulders and the top of the uniform pants, and the lower level is a line at the hollow beneath the kneecap"

Here's a visual of what the rulebook defines are the vertical constraints of the strike zone:

Looking back at the data table, SZ_Top is the distance in feet from the ground to the top of the current batter's rulebook defined strike-zone (measured from the video by the PITCHf/x operator, the operator sets a line at the batter's belt as he settles into the hitting position). SZ_Bot is the distance in feet from the ground to the bottom of the current batter's rulebook defined strike zone (PITCHf/x operator sets a line at the hollow of the knee for the bottom of the zone).

Plate_Z is the vertical placement of the ball. If the value is between the appropriate sz_top & sz_bot values, it is considered a strike.

To recap, for a pitch to be called a strike, the plate_x value must be between -0.833 & 0.833 and the plate_z value must be greater than or equal to the sz_bot but less than or equal to sz_top.

The "description" column tells us what the pitch was called (ball or strike) by the homeplate umpire. The "AdjustedCall" is a variable I created that checks the plate_x & plate_z values to appropriately call the pitch as a strike or ball given the sz_top, sz_bot . and horizontal constraints of the strike zone.

Let's confirm that Kershaw's curveball to J.D. Martinez checks off the boxes for a called strike.

We already checked that the plate_x value is within the horizontal constraints (-0.833ft < 0.8207ft < 0.833ft).

With a plate_z value of 3.43ft, it is within the strike range vertically since its less than sz_top (3.6411) & greater than sz_bot (1.6297).

According to the rulebook defined strike zone, this pitch is a called strike, but Tim Timmons calls it a ball, swinging the count from what is supposed to be a 1 ball, 2 strikes to a 2 ball, 1 strike count.

This difference itself is huge; In a 2-1 count, JD Martinez batting average was a .565 while in a 1-2 count, his batting average was an abysmal .124! (Baseball Reference)

Looking into the at bat further, the "2-1" count pitch is a beautifully placed fastball on the inside corner. this could have been a called strike 3 & the inning would have ended there. Instead, Kershaw is forced to throw a 4th strike which gets smacked into deep center field for a go-ahead run scoring double. The Red Sox went on to win that game, 8-4.

This is one of many pivotal situation that have occurred throughout last season that have affected the outcome of games.

I want to keep these posts relatively short, so this will serve as an introduction to the controversy with a bit of raw data & video evidence.

For a more in-depth analysis of the 2018 regular season's home-plate umpires, refer to:

excel spreadsheet: https://docs.google.com/spreadsheets/d/14nPCZ5PVMOtTK18WPmc5OnyBPvyHtWVCF4gxzE9zjSA/edit#gid=0

my github repository: https://github.com/ayusharora99/2018_Umpires

Thank you for reading!