As of this writing on 4/25/2022, HRs are down, damage and distance on barrels are down, and both Alan Nathan and Rob Arthur have observed that the drag coefficient of baseballs this year is substantially increased. This has led to speculation about what has changed with the 2022 balls and even what production batch of balls or mixture of batches may be in use this year. Given the kerfluffle last year that resulted in MLB finally confirming that a mix of 2020 and 2021 balls were used during the season, that speculation is certainly reasonable.
It may well also turn out to be correct, and changes in the 2022 ball manufacture could certainly explain the current stats, but I think it’s worth noting that everything we’ve seen so far is ALSO consistent with “absolutely nothing changed with regard to ball manufacture/end product between 2021 and 2022” and “all or a vast majority of balls being used are from 2021 or 2022”.
How is that possible? Well, the 2021 baseball production was changed on purpose. The new baseball was lighter, less dense, and less bouncy by design, or in more scientific terms, “dead”. What if all we’re seeing now is the 2021 baseball specifications in their true glory, now untainted by the 2020 live balls that were mixed in last year?
Even without any change to the surface of the baseball, a lighter, less dense ball won’t carry as far. The drag force is independent of the mass (for a given size, which changed less if at all), and F=MA, so a constant force and a lower mass means a higher drag deceleration and less carry.
The aforementioned measurements of the drag coefficient from Statcast data also *don’t measure the drag coefficient*. They measure the drag *acceleration* and use an average baseball mass value to convert to the drag force (which is then used to get the drag coefficient). If they’re using the same average mass for a now-lighter ball, they’re overestimating the drag force and the drag coefficient, and the drag coefficient may literally not have changed at all (while the drag acceleration did go up, per the previous paragraph).
Furthermore, I looked at pitchers who threw at least 50 four-seam fastballs last year after July 1, 2021 (after the sticky stuff crackdown) and have also thrown at least 50 FFs in 2022. This group is, on average, -0.35 MPH and +0.175 RPM on their pitches. These stats usually move in the same direction, and a 1 MPH increase “should” increase spin by about 20 RPM. So the group should have lost around 7 RPM from decreased velocity and actually wound up slightly positive instead. It’s possible that the current baseball is just easier to spin based on surface characteristics, but it’s also possible that it’s easier to spin because it’s lighter and has less rotational inertia. None of this is proof, and until we have results from experiments on actual game balls in the wild, we won’t have a great idea of the what or the why behind the drag acceleration being up.
(It’s not (just) the humidor- drag acceleration is up even in parks that already had a humidor, and in places where a new humidor would add some mass, making the ball heavier is the exact opposite of what’s needed to match drag observations, although being in the humidor could have other effects as well)
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