How the dual ball season may have affected the Yankees

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If you haven’t yet read Bradford William Davis’ reporting on MLB’s usage of two different baseballs during the 2021 season, you’ll want to do so now. It’s essential reading. Davis, along with Dr. Meredith Wills’ research, showed clear cut evidence of two different balls being used in 2021. The league admitted as such, but blamed it on COVID-19.

The two different balls had different specifications and thus resulted in different performance outcomes. The league didn’t inform anyone about this, players included, though the players may have had a hunch something was awry. The original plan was to introduce a single and more consistent ball in 2021. Instead, balls from prior year specifications were circulated. There’s already plenty of speculation about how the league could have done this — I have a Yankees-related theory to present, too — but first, some hypotheses about how the balls were mixed in, straight from the report:

While the league blames COVID-19 for the dual-ball season and says it won’t happen again, some of the players reached by Insider entertained more conspiratorial hypotheses. For example: What if MLB sent a disproportionate number of either ball to a specific park or for a specific set of games, putting its thumb on the scale to create incentivized to introduce two baseballs” to try to produce higher- or lower-scoring games.

The National League pitcher who replicated Wills’ study believes MLB “is more or less incentivized to introduce two baseballs” to try to produce higher- or lower-scoring games.

“You know, send a bouncier baseball, lighter baseball — whichever flies more — to a primetime series,” he told me, listing off marquee matchups like Yankees-Red Sox and Mets-Phillies. “Then,” he suggested, send more dead baseballs to “Texas versus Seattle. Or, you know, Detroit versus Kansas City. No one’s going to bat an eye.”

On the other hand, he speculates, the league could flip that approach around and send high-octane balls to low-profile games and “produce more offense,” which might “put more seats in the stands. Just continue to bring up fan engagement.”

Again, these are merely unproven hypotheses. But they sure are interesting, no? Here’s my theory: MLB consistently supplied the new balls to games played at Yankee Stadium. In other words: the baseball that doesn’t travel as far was used exclusively in the Bronx, whereas the Yankees played with a mix of the two elsewhere. Here’s some data I was able to pull via Baseball Savant:

2021 Yankees hitters’ results on pop ups, line drives, and fly balls based on contact quality.

Now, it’s important to caveat that the data I pulled is from the entire season, meaning that it includes data before and after the foreign substance crackdown. Sticky stuff does impact drag, which can make for an inconsistent environment in the data I grabbed. Plus, weather plays a role, further complicating environments as no single day is the same as another. I obviously don’t have access to every single baseball used at Yankee Stadium, either.

Those notes aside, it’s still clear that there’s a big difference in performance at home vs. on the road for Yankees’ hitters. Any way you slice it — all contact qualities, Hard Hits, or Barrels — the Yankees hit the ball further on the road. And to get more granular, the data was very consistent broken down by launch angle:

Once above the 14 degree launch angle, balls consistently traveled further for the Bombers away from Yankee Stadium. Now, let’s do a similar check, this time with exit velocities:

Again, the data is consistent, especially as exit velocities enter the Hard Hit (95+ MPH EV) range.

Taking things one step further, let’s take a look at how individual players fared:

Yet again, away distance is king. Yes, there are two exceptions: Giancarlo Stanton and Gary Sánchez, but all others experienced a discrepancy.

Remember this chart from my season review of DJ LeMahieu?

Barrels & Solid Contact at Yankee Stadium only (2021).

Huh! I wonder what happened here?! Perhaps if the league didn’t funnel the new baseball to the Bronx, LeMahieu’s season looks a lot different. Grr…

There sure is a lot of data pointing to something strange that went on in the Bronx. Seems reasonable to think that the league would want to avoid sending the old ball to Yankee Stadium, right? Especially given its propensity to yield home runs. Had they mixed in the old ball (as they did elsewhere), there likely would have been more home runs (akin to prior years), and people would have wondered earlier about the “new” baseball not actually changing anything.

I’m curious to see if there’s evidence of this at other ballparks. Data from one team at its home ballpark vs. the road isn’t quite enough to prove a leaguewide conspiracy, though I feel it’s pretty safe to assume that the Yankees played with the new ball at home and a mix away. Whether my theory is accurate or not, the league’s mishandling of this situation has opened itself up for speculation just like what I’ve presented today.


Thoughts as the lockout looms


The Views From 314ft Podcast Episode 81: Locked-out and Loaded


  1. Scout

    Remarkable that baseball, which draws more fans when there is more offense and more home runs, would deaden the baseball to reduce both. If MLB operated a gun range, it would be circular.

  2. Coolerking101

    Someone already broke down all the games on Twitter (@yankeesSlut) and notably, the Yankees magically hit MUCH MUCH better whenever their games were nationally broadcast:

    This is what the Yankees as a team slashed in 2021 games broadcast on national (non-simulcast) television:


    This is what they slashed on games broadcasted locally:


    More than anything, note the difference in slugging percentage.

    • 4thGen

      This comment is spot on and gets to the heart of baseball which we as fans want to conveniently ignore. MLB is an industry, the teams are companies, the players are the employees, the games are the product, and fans are the customers. TV broadcasts are the means by which to get the product to the customers.

      If more customers will pay (tune in for games) for a more enjoyable product (see more home runs), then companies (teams) would be stupid not to package their product (games) in such a way that more will be sold. Why would they not bias the materials (baseballs) for that product in such a way that you can sell more of said product?

      Team owners, media conglomerates, and players are all in business to make money and this is just simple economics. As a lifelong Yankees fan, I don’t like it, but to not see this reality would be willful ignorance.

      • Home runs are fun, but I actually like the running game on offense and an artfully pitched game more. I guess I don’t represent the masses. I miss watching Masahiro Tanaka pitch, although Kluber and Nestor were also entertaining.

  3. Maybe I’m misremembering but weren’t the Yankees in a slump and then they played in the Field of Dreams game and there were homers galore just flying into the corn?? Really makes you think something was up for sure

  4. Dani

    The weirdest thing for me: why do they still produce more old balls than new ones? Doesn’t make any sense to me. Obviously there’s something fishy going on. Considering gambling on baseball is now legal … there should be some serious investigation about this.

    And of course this hurt the Yankees a lot if they used the new balls only in YS. They’re a team built to hit HRs and when HRs go down this team obviously will lose part of it’s strength. Maybe it wasn’t coincidence that they had their worst win% at home since 2015.

    The saddest part about this is that there’s not nearly enough media coverage on this. This is a huge story and it should get at least as much attention as the CBA talks or the Astros cheating scandal. This in itself is something that hurts the integrity of the game immensely. Are they manipulating games for “competitive balance” and/or push/punish certain teams? If we can’t trust the results on the field … what else can we have trust in?

  5. MikeD



    I like it. I don’t like that they might have done it, but I like your thinking. It’s all we got during the beginning of lockdown days.

    MLB consistently screwing around with the baseball is incredibly frustrating. Forget about fans for the moment, forget about the players, what about the teams? How do they decide to sign a hitter or a pitcher if they can’t accurately gauge who he is? The Yankees went and gave DJLM a $90M contract based on who they thought he was. Well, what is he? What will he be next year?

    MLB is built around the baseball. It’s the most crucial aspect of the game, from every pitch, every swing of the bat, every error, every catch, every spectacular play. Scary that the key component of the game, the baseball, can’t be trusted.

  6. Feliz Navideddard

    I don’t think it made a lick of difference, Derek. Does everything have to be a conspiracy theory nowadays? Don’t miss Derek and Bobby on Joe Rogan’s podcast tomorrow! People are always looking for excuses for why this season was a disaster and they want to blame everybody except the players. This club couldn’t even make contact with the baseball. That’s why they were awful, not some imaginary doctored baseball from a Wuhan lab. Gallo hit .100 for christ sake! that wasn’t the baseball. And it didn’t hurt other clubs. The Rays mashed dinger after dinger. Do you really think MLB is sending them the good baseballs? They’d be sending them to New York, Boston and LA not Tampa Bay, Milwaukee and Atlanta. They juiced the balls in 2020 leading to crazy numbers and unfortunately this FO made bad decisions based on those video game stats and now we’re paying the price for it. Now that the balls are back to normal we’re going to have to learn how to hit for contact and Cole is going to have to learn how to pitch without foreign substances. But other clubs adjusted and thrived and we didn’t.

    • Mickey McCarthy

      Which balls are back to normal? The juiced balls or the dead balls. Things can’t be normal when there is no consistency

  7. dasit

    would be interesting to do some sort of exit velocity-to- distance study by team. one hypothetical i’ve seen floated is mlb giving the angels the bouncier ball to assist ohtani in becoming a megastar (he doesn’t need the help but you get the idea)

  8. Bartholomew "Bart" Meshir

    Interesting indeed. Maybe they saw that it may have been getting too obvious to see that there were two balls so they pushed through the crackdown on sticky stuff to mess with the data. It seemed everyone was surprised that they did it mid season. They couldn’t wait or it would have been too obvious at the end of the season if they did nothing. Manfred is a “dead brain person” and really needs to go. The lack of punishment for cheating, the moving of the all star game BS with the Braves. I’m sure they didn’t get any juiced balls and now this.

  9. Jack H.

    The baseball is THE essential piece of equipment for this sport, and the league that runs the sport:

    a) Owns the company that manufactures baseballs
    b) Can’t be trusted to produce balls that are uniform, typically season-to-season, but now within the season as well!

    This is just a criminal handling of the game, and shows just how far the league has fallen to pieces under Manfred’s stewardship (notice I didn’t say leadership). I thought I couldn’t dislike someone more than Bud Selig. Well, thanks for proving me wrong, Rob.

    What an embarrassment.

    • dasit

      well said and completely agree. mlb gets zero benefit of the doubt on this. manfred is the definition of “useful idiot”

      • Kiwi

        Yep…couldn’t agree more. Manfred is a man of these times though…..we celebrate & elevate people like him with no moral compass encumbering their quest for just more.

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