Baseball Experiences Modest Offensive Gains Post-Sticky Stuff Crackdown

Major League Baseball’s sticky stuff crackdown is working. Since the June 3 warning that increased enforcement of the foreign substance rule was coming, spin rates have fallen league-wide. The league-average spin-to-velocity ratio on four-seam fastballs, which sat comfortably above 24.5 rpm/mph for the entirety of the 2020 season and the beginning of the ’21 season, has fallen to under 24 rpm/mph for the first time since the beginning of ’19. This is what that enormous drop looks like visually:

The crackdown has had plenty of consequences, all of which have theoretically had a significant impact on the game. I touched a little bit on one of these outcomes — whether it was fair to ask pitchers to alter their stuff dramatically in the middle of a season — in a July 2 article on Garrett Richards, who claimed that he needed to try “to figure out how to pitch again” post-enforcement. But there has been one outstanding question all along: How will this impact offense? In a year that started with some of the lowest batting averages in baseball history and with run scoring heavily concentrated in home runs, that was of the utmost importance in the minds of baseball-followers, including those who work for the league and for teams. Cubs president Jed Hoyer, for example, called the impact of the sticky substance enforcement “a huge variable” in determining which players Chicago could target at the July 30 trade deadline.

In an article leading up to the changes in enforcement, I covered the potential impact the crackdown would have on offense with a focus on the effect of spin rates on batter performance. The trend was clear: Batters hit much better on four-seam fastballs with less velocity-adjusted spin, and in a world in which fewer pitches are thrown with elite spin, they should have an easier time at the plate. One executive even told Stephanie Apstein and Alex Prewitt of Sports Illustrated that he thought better enforcement of Rule 6.02(c) could actually have an outsized impact on reviving offense around the league, potentially lessening the pressure on baseball to institute rule changes to create more balls in play, higher batting averages, and more non-homer scoring overall. “I think people would be absolutely shocked if they actually enforced this, how much you’ll start to normalize things without rule changes,” they said.

As I have researched the impact of the sticky stuff enforcement on offense, that specific quote stuck with me; I almost expected a shift in baseball’s run environment overnight. I’m not entirely sure what I thought would be coming, whether it would be more homers or more balls in play as a result of fewer strikeouts, but I did think the game would look and feel noticeably different. Instead, as Rob Arthur put it at Baseball Prospectus, the league looks more like 2019 than it does, say, 2008. As he noted, the reason these trends aren’t wholly reversing the three-true outcome style of baseball is due to other factors — a ball that flies further, better optimized launch angles, and continued improvement of pitching — that still exist in a post-enforcement era.

That isn’t to say that nothing has changed. The Washington Post and The New York Times each conducted analyses of their own, with the Post reaching a similar conclusion as Arthur’s: contact rates are up. The Times, meanwhile, used FanGraphs data to show an uncharacteristic midseason increase in on-base percentage, from .312 pre-June 3 to .324 to in the period between June 15 and July 18. It’s a noticeable increase (and, again, an uncharacteristic increase for the middle of a season), but the style of baseball we’re witnessing has not drastically changed.

That’s what I found when doing my research. Despite the decrease in spin-to-velocity ratio, offense has ticked up only slightly. Batters have seen modest gains in performance, with even the greatest overestimate of the increase (not including weather-related effects) demonstrating a 13-point wOBA increase. That is admittedly a big shift, but after trying to account somewhat for weather-related effects, we find that the adjusted change might not be as massive as we have been expecting.

For example, here is the change in total offensive output over two periods since 2002, with Period 1 being Opening Day through June 2 and Period 2 being June 3 through July 19. We have seen the largest percent change in wOBA this season — a sign that may confirm that sticky stuff enforcement is helping — but it’s not enormous in comparison to prior years:

The league-average wOBA jumped by 4.2% from Period 1 to Period 2, a shift that outpaces all prior seasons listed above. But within the past five full seasons (2020 excluded), we have seen four of the largest shifts, possibly due to a larger reliance on home runs that has created an even larger disparity between April and July run-scoring than in years prior. In 2016, for example, we saw a 2.9% increase, and ’17 and ’19 each saw 2.8% increases. The only oddball in this subset is 2018, which saw no change between the two periods. If we say that 2021 would’ve acted like 2019, with its 2.8% increase due to normal weather-related factors, the contribution of sticky stuff enforcement to overall output is muted significantly: just five points of wOBA. Even if we say that there’s a 1.5% weather-related effect here, the sticky stuff enforcement is worth eight points. On a league-wide scale, these are notable changes, but they also echo Arthur’s point that there’s more work to be done if offense wants to shift away from the reliance on the three true outcomes.

There are some other interesting things going on here, though, suggesting that there is perhaps a lag in offensive improvements related to greater enforcement. For one, focusing particularly on four-seam fastballs, the nice trend showing how spin yielded worse outcomes for hitters has been altered:

Some of this may be due to sampling, but take a comparison of the 22–23 to 26–27 groups in Periods 1 and 2. In the former, hitters posted a collective wOBA that was 24 points higher on fastballs than those in the latter — a huge 7% increase. Since June 3, though, the wOBA on fastballs in the 22–23 group has remained relatively steady, and the wOBA on fastballs in the 26–27 group has jumped by 12 points, narrowing the gap from 24 points to 13. While this may seem good for hitters — they’re producing much better results on higher spin fastballs, after all — weather should theoretically be less of a factor when comparing the differences between groups. And if hitters are seeing more lower-spin fastballs than they were before but still aren’t seeing the same gains in production, that leaves us with an overall small effect.

Think about it this way. If you saw 10 plate appearance-ending fastballs in Period 1, with half in the 22–23 group and half in the 26–27 group, you would have been expected to produce a .345 wOBA. But in Period 2, you might be seeing eight fastballs in the 22–23 group and just two in the 26–27 group. In this case, your wOBA only improves to .354. These changes aren’t as drastic on the macro level as they are in this example, but it’s a curious shift in performance that I can’t quite put my finger on, and I’m also having a moderately difficult time claiming “small sample” as the reason for it. Here is the actual data on how those groups have changed:

% of PA-ending Four-Seam Fastballs
SVR Group Period 1% Period 2% Difference
<20 0.89 1.93 1.04
20-21 7.69 12.76 5.07
22-23 27.58 36.31 8.73
24-25 38.38 37.02 -1.36
26-27 20.47 10.64 -9.83
28-29 4.28 1.17 -3.11
>=30 0.70 0.17 -0.53

Spin is definitely down, and a large portion of the shift is coming from the 26–27 group that is being moved into the 22–23 group. The shift in the distribution of pitches can be highlighted more here:

Huge offensive gains haven’t come. If we were to use the through-June 3 figures for performance and apply the post-June 3 distribution of plate appearances to them, we should have expected to see a non–weather-impacted wOBA increase of about 2%. Include some level of climate effects, and we likely should have seen an increase in four-seam performance of about 5% or so. This may be evidence to suggest that a further increase in offense is coming, but even still and as mentioned throughout, it likely will not be enough to shake up baseball as we know it.

Further research will be necessary throughout the season to evaluate whether anything changes or, if this trend holds, why we’ve seen such a notable change in batter performance on different levels of spin rates. But for now, overall offensive gains are relatively modest, and the game of baseball we’re watching is largely the same, with the only exception being the sticky stuff checks at the end of every inning. As Joey Gallo put it to Matt Snyder of CBS Sports, “Guys still have ridiculous stuff … it’s still hard to hit.”

Devan Fink is a Contributor at FanGraphs. You can follow him on Twitter @DevanFink.

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1 year ago

My only complaint regarding the MLB’s crackdown on foreign substances is that is should have started several years ago. But, true to form, MLB just ignored the problem until it became a visible eyesore on the sport.

Smiling Politely
1 year ago
Reply to  v2micca

Yeah; doing it mid-season (not even over the AS break!) was just foolish-on-its-face and made everyone look bad unnecessarily

1 year ago
Reply to  v2micca

The only reason it became a “visible eyesore to the sport” is because feckless media fearmongered it into a CRISIS of CHEATING on par with the STEROID ERA.

The central argument that caused this entire mess was that sticky stuff increases spin rate AND spin rate has a massive impact on offensive production that is in large part to blame for the type of game being played right now.

In reality, what we’re seeing in very obvious terms is that the “and” part was wildly wrong.

“As he noted, the reason these trends aren’t wholly reversing the three-true outcome style of baseball is due to other factors — a ball that flies further, better optimized launch angles, and continued improvement of pitching — that still exist in a post-enforcement era.”

What Rob doesn’t have the fortitude to admit here is that he and all analysts who have been proven wrong did an absolutely dreadful job of isolating variables. Pure junk science, plain and simple.

There isn’t a person on this planet who could spot the difference between the style of game played pre and post crackdown. The entire thing was massively overhyped.