Is There A Postseason Bat Speed Bump?
An early look at adrenaline’s effect on bat speed.
The Major League Baseball Postseason is not only the most exciting event on the baseball calendar, but it is, in my opinion, the greatest sporting event of the year. Over just five days of action, there have been numerous exciting games, and this postseason is shaping up to be one of the “best” in recent years. Not only is the postseason exciting due to the eventual crowning of the World Series champion, but the statistical randomness of such small sample sizes can make a significant impact on a team’s postseason result. Events that would be considered statistical noise in the regular season, such as a high batting average on balls in play or an underwhelming command outing by a starting pitcher, can often have a significant impact on whether or not a team will advance to the next round.
In my opinion, one of the more intriguing statistical phenomena of the postseason is the increase in velocity that many pitchers experience when pitching in October. As described in a FanGraphs article by Davy Andrews in 2022, pitchers often experience increases in velocity during their Postseason outings due to the increased adrenaline players experience when playing in such a high-stakes environment. According to Andrews’s research, pitchers experience on average a 0.5 MPH velocity increase on their four-seam fastballs during the postseason, when accounting for selection bias. These velocity increases have an effect on the quality of a pitcher’s arsenal, as I have anecdotally noticed that many pitchers have experienced an increase in their postseason aStuff+ compared to their regular season results. This increase is believed to be the result of heightened adrenaline during postseason games, and if pitchers are capable of such adrenaline-influenced improvements, it raises the question of whether hitters experience a similar boost in their bat speed during the postseason.
Back in May, Statcast released its first batch of public bat tracking metrics, allowing for the public to analyze the bat speed and swing length of nearly every swing taken during the 2024 Major League Baseball season. As I have described numerous times before on this blog, analyzing a hitter’s bat speed is important as it can be utilized as a predictive metric to explain and predict a given hitter’s exit velocity (an increase in bat speed is related to an increase in exit velocity). Given the increase in velocity and pitch arsenal quality experienced by pitchers in the postseason, I believe that it makes intuitive sense to analyze whether hitters experience a similar increase in bat speed when playing in a high-stakes postseason environment.
For the analysis, I simply calculated the average bat speed (per Statcast’s formula) for all swings during the 2024 Major League Baseball regular season and postseason. I also calculated the average bat speed for the regular season and postseason, grouped by the following results: extra-base hits, singles, foul balls, and whiffs. The figures below are raw bat speed numbers and do not account for any selection bias that might occur in such a dataset. Onto the analysis!
As shown by the tables above, there does appear to be a bat speed increase present during the postseason, with hitters swinging on average 0.7 MPH harder during the postseason than they did during the regular season. When grouped into varying events, the increase continues to occur universally, with hitters particularly swinging harder on their foul balls and whiffs than they did in the regular season. While the postseason sample size is much smaller than the regular season sample size, these results indicate that a postseason bat speed increase likely exists.
Among players with at least 10 swings in the postseason, Jason Heyward experienced the biggest bat speed bump, with his average bat speed increasing from 73.3 MPH to 77.2 MPH, a nearly 4.0 MPH increase. Notably, three of the five largest bat speed gainers (Vinnie Pasquantino, Tommy Pham, and Yuli Gurriel) are members of the Kansas City Royals. Luis Arraez, known for having the lowest average bat speed in Major League Baseball in the regular season among qualified hitters, has increased his average bat speed by 1.8 MPH to 64.9 MPH in the postseason (which is still very low).
On the surface, it appears that there is an increase in average bat speed among hitters during the postseason, but it is still too early in the postseason to definitively conclude whether or not an increase exists. With the sample size of this analysis consisting of 316,595 regular season swings and 2,123 postseason swings, there is room for the results of this analysis to change once more postseason swings are added to the dataset over the upcoming three weeks. It is also worth repeating that I did not account for selection bias in this analysis, and while it appears that the postseason consists of teams that are rather evenly distributed as it pertains to average bat speed rankings (with perhaps a slight skew towards higher average bat speed teams), it is possible that players with lower bat speeds during the regular season have not experienced much playing time in the postseason, skewing the results towards a higher average bat speed.
This leads to the question, what are the takeaways from this analysis? As with most Postseason analyses, there are not a lot of macro takeaways that result from such a selective analysis, but one takeaway is that it appears likely that a postseason bat speed increase does exist. A larger sample size of postseason swings will be needed to arrive at a definitive conclusion, and I am looking forward to revisiting this topic once the postseason concludes. Perhaps further research could be conducted on what variables determine whether a player is likely to experience a bat speed increase in the postseason, which could play a role in formulating a more effective game plan against opposing hitters. Similar to the increase in velocity that pitchers experience in the postseason, hitters appear to experience a bat speed increase in the postseason, and these phenomena are only two of the many factors that make October baseball one of the most exciting events in all of sports.
Thanks for reading!
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