Introducing Pitching Stat LBAbip
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BAbip, batting average on balls in play, serves as a valuable statistic for gauging pitchers' luck in the frequency of balls in play (excluding homeruns) that lead to base hits. Conventionally, a pitcher’s BAbip is compared to the league average BAbip when assessing how lucky or unlucky a pitcher has been. In this analysis, I’ll introduce a more sophisticated point of comparison: location-based batting average on balls in play (LBAbip). I will use LBAbip to identify pitchers who are likely to regress to the mean in 2024.
Figure 1 below depicts league-wide BAbip, grouped by location. As evident from the figure, the middle and lower portions of the strike zone have higher BAbips, while the top of the strike zone and up above the zone have lower BAbips.
Figure 1: League-wide BAbip, grouped by location. The middle 16 rectangles represent the strike zone.
A pitcher’s LBAbip is the arithmetic mean of the league-average BAbips at the locations in which his batted balls were pitched. LBAbip is a more reliable point of comparison than league-average BAbip for a pitcher’s luck, because it takes into account his pitch locations, instead of assuming league-average pitch location.
Let’s take a look at which pitchers have lowest BAbips relative to their LBAbips in 2023, shown in Table 1 below. I incorporated Stuff+ (https://library.fangraphs.com/pitching/stuff-location-and-pitching-primer/) into this analysis because some pitchers can succeed even when placing pitches in high BAbip zones, thanks to the velocity and movement of their pitches. Shohei Ohtani and Corbin Burnes shouldn't be automatically categorized as "lucky"; their ability to prevent high batting averages is attributed to their exceptionally nasty stuff.
Table 1: BAbip, LBAbip, Difference (LBAbip – Babip), and Stuff+ for the ten highest Difference pitchers with at least 500 balls in play in 2023.
Tyler Wells, Domingo German, Wade Miley Clayton Kershaw, Colin Rea, Jordan Lyles, and Reese Olson should expect to have a higher percentage of their batted balls result in hits in 2024. Tony Gonsolin will likely miss the 2024 season after undergoing Tommy John surgery.
Let’s look at which pitchers had the highest BAbips relative to their LBAbips in 2023.
Table 2: BAbip, LBAbip, Difference (LBAbip – Babip), and Stuff+ for the ten lowest Difference pitchers with at least 500 balls in play in 2023.
As we can see from Table 2, Dylan Cease and Hunter Greene are the two pitchers most likely to see a reduction in the percentage of their balls in play that result in hits in 2024. They both have stuff significantly better than MLB average and are not locating an inordinate number of pitches in the high BAbip zones.
