This study analyzes the effects of the MLB foreign substance ban on pitcher spin rates and batting averages with different pitches. During the 2019-2020 and 2020-2021 MLB seasons, pitchers throughout the league were accused of putting pine tar, Spider Tack, and other banned substances onto baseballs in order to create an artificially high spin rate. A higher spin rate makes hitting much harder and batters tend to strike out much more often. These factors contributed to a reduction in runs scored per game and generated frustrated fans. Consequently, the MLB implemented a substance ban in 2021 over concern that interest in the sport was declining. This study was conducted to determine if spin rates decreased on specific pitches such as fastballs, curveballs, sliders, and change-ups after the substance ban was implemented and if the increase in pitched ball spin rates correlated with a decline in opponent hitting statistics. To determine the answers, 12 regressions were run, first on opponent batting average before and after the implementation of the foreign substance ban, pitcher spin rates before and after the implementation of the ban, and lastly, on regressed spin rates on a collection of hitting statistics to determine if there is any correlation. Four types of pitches were selected to provide a more comprehensive analysis to determine how the ban affected the spin rates and batting averages against each pitch type as well as if the ban was effective. It was discovered that average spin rates experienced a statistically significant drop in every pitch after the implementation of the foreign substance ban, however, batting averages only had a statistically significant change against fastballs after the foreign substance ban was implemented, which is not the increase that was expected. However, it appears that the foreign substance ban is doing its job to deter pitchers from utilizing foreign substances.

First Advisor

Matt Warning

Date of Completion

Winter 12-15-2022

Degree Type


Degree Name

Bachelor of Arts in Economics

Date of Award

Winter 1-17-2023

Included in

Economics Commons