The “juicing claim” by Verlander has gained traction among players and fans.
It’s clear that home runs are on the rise. Home runs per plate appearence is at 3.5%. This is a record high. If players continue at this pace, they will have hit over 6,600 home runs by the end of the season, breaking the previous record from 2017 by more than 500.
Last year, after years of denying that they altered the balls in order to increase the home run rate, league officials admitted the ball was changed. However, they blamed the suppliers. admitted earlier this year that the core of the ball had been altered.
This topic is something we are familiar with, as we have written a book called ” Corked: Tales Of Advantage In Competitive Sports“.
Recent changes to the baseball are certainly playing a part in the increase in home runs. Could other factors like advanced analytics and the climate also be at fault?
Baseball – How to break it down
Rawlings produces around one million baseballs per year to be used in MLB.
Official baseballs are made of six materials : a rubberized center (called “pill”); two hemispherical shells of black vulcanized rubber molded in a clamshell shape, a layer red rubber, wrapped wool, two flaps cowhide leather and 88″ of wax-coated, red thread.
A growing body of evidence indicates that the materials used to make the official baseballs of the Major League Baseball have changed in density and chemical composition since 2015.
The ball’s surface and core have seen the most significant changes.
In 2016, FiveThirtyEight conducted an investigation that found official baseballs to be more bouncy and less resistant to air starting in 2015.
FiveThirtyEight compared the balls produced before 2015 and those made after. The study found that core density of baseballs made after 2015 decreased by an average of 40%. Compositional analysis revealed that the pills produced after 2015 contained 7% more silicon and 10% more rubber. These changes are correlated with a lower pill mass and an increased bounce.
Major League Baseball’s 84 page report, released nearly two years after FiveThirtyEight, acknowledged that there were aerodynamic improvements in baseballs – specifically the balls were smoother. The league said that this was not due to changes made by Rawlings in the manufacturing process. MLB said that the ball’s condition was probably due to slight differences in Rawlings’ materials and the way they were stored.
Rawlings, for example, does not process its leather in-house and instead purchases it. This could lead to a smoother leather surface if they used a different tanning process. Once hit, baseballs with a smoother surface will move more easily through the air. The change is minor, but it’s important.
The ball’s thread is another important factor. Journalists from The Athletic , an online sports publication, deconstructed baseballs. They found that the laces on the newer balls are 9% thicker.
The investigator speculated, that thicker laces could make it easier to construct a ball with fewer air bubbles, which would allow it to be hit more easily.
There’s another explanation that isn’t under the control of the players, league or manufacturers: the climate.
In southern Europe and North Africa, cork is harvested from the bark on the Cork Oak Tree. A changing climate in these regions is causing some concern that the cork quality will decline. Wine manufacturers have already begun looking for alternatives to make wine corks. Baseball makers are more interested in the mechanical response the cork has inside the ball than wine makers.
Baseballs are made from rubberized, engineered cork. It’s possible, however, that their composition and purity may change with the weather, just like wine corks.
Humidity in the ball and on it can also reduce its inertia, and its reaction to being hit by a baseball bat. In 2018, CBS reported Major League Baseball will require that all teams use air-conditioned rooms for baseball storage in 2019. HVAC systems are designed to lower temperature and reduce humidity. In humid ballparks, it’s possible to increase the life of a ball by reducing its humidity.