Does the Defensive Shift Employed by an Opposing team affect an MLB team's Batted Ball Quality and Offensive Performance?

Presented by:
Jeremy Bruton (Lawrence University)

This project studies proportions of batted ball quality across the 2019 MLB season when facing two different types of defensive alignment. It also attempts to answer if run production is affected by shifts. Batted ball quality is split into six groups (barrel, solid contact, flare, poor (topped), poor (under), and poor(weak)) while defensive alignments are split into two (no shift and shift). Relative statistics come from all balls put in play excluding sacrifice bunts in the 2019 MLB season. The study shows there to be differences in the proportions of batted ball quality relative to defensive alignment. Specifically, the proportion of barrels (balls barreled) against the shift was greater than the proportion of barrels against no shift. Barrels also proved to result in the highest babip (batting average on balls in play) + slg (slugging percentage), where babip + slg then proved to be a good predictor of overall offensive performance measured in woba (weighted on-base average). There appeared to be a strong positive correlation between babip + slg and woba. MLB teams may consider this data when deciding which defensive alignment to play over the course of a game. However, they will most likely want to extend this research by evaluating each player on a case by case basis.