Let’s Discuss the New Ball

In recent years, Major League Baseball has undergone numerous changes, and the 2021 season has been no exception. In fact, beginning last year, changes to the game have felt like a nonstop engine—with more changes certainly on the horizon.

However, let’s put that aside for a moment and focus one particular change that took place at the start of the 2021 season: MLB tampered with the ball. Again. They even admitted to it this time. You see, MLB decided that they no longer wanted to boost home run totals, instead opting to “deaden” the ball in hopes of simultaneously boosting other forms of offense.

That means, by design, fewer balls leaving the yard and more turning into singles, doubles and triples. You know, “pace-of-play” and all that. Regardless of your thoughts on this decision, the reality is that it worked... kind of. Today, we’re going to talk about the sort of offensive output we’ve seen this year and how it compares to the most recent “normal” season (2019).

Of course, it isn’t as simple as just saying “MLB killed home runs.” That isn't true. At least, it isn’t entirely true. The new ball definitely does its job in suppressing offense, but the trouble has been pinpointing exactly how and when it does so. Thankfully, a lot of the hard work has already been done in this piece by Devan Fink. Using similar Batted Ball Events (or BBE) he cited in his analysis, I’ll be building off what he started there. First, let’s get a general understanding of league-wide hit probability on a specific batted-ball type. Let’s look at a BBE with an Exit Velocity (or EV) of 100+ MPH and a Launch Angle (or LA) between 16-24 degrees (or basically, line-drives).

Let’s take a second to digest those numbers. From April through June of 2019, if a ball was hit 100+ MPH, at a LA between 16-24 degrees, the batter had a 72% chance of getting a hit, and a 65% chance of getting an extra-base hit, with a 27% chance of it becoming an out. Now, let’s look at the exact same batted-balls, but this time let’s see what the hit probability was this year with the new ball.

As you can see, there are definitely some changes to hit probability this year. On this BBE, from 2019 to 2021, we saw a 5% drop in total hits (including a 6% drop in home runs) and a 5% increase in field outs. While 5% may not sound like a lot, remember that we’re talking about league-wide data here. A 5% decrease in hits in this example alone is a loss of ~93 hits all said and done. That’s the difference between a few wins and losses for a lot of teams.

Now that we’ve seen the outcome difference between 2019 line-drives and 2021 line-drives, let’s take a look at the outcome difference for well-hit fly balls. Specifically, batted-balls with an EV of 100+ MPH and a LA between 25-35 degrees.

Once more, let’s dissect these percentages a bit before moving forward. From April through June of 2019, with that BBE, hitters enjoyed a 75% home run rate, an 81% extra-base hit rate and an overall 82% hit rate. So with the 2019 ball, when batters hit the ball with those set parameters, they could expect to get out just 17% of the time. Now, let’s look at the exact same BBE, this time with the 2021 ball.

Here, we see a similar trend to the one we had with the prior line-drive comparison. On this BBE, from 2019 to 2021, we saw a 5% decrease in home runs, a 4% decrease in total hits and a 4% increase in field outs. Batters who hit the ball within those set parameters in 2021 could expect to get out 21% of the time.

So once again, we’re seeing the new ball put a damper on offense, especially when it comes to hitting home runs. Between those two subsets of batted-ball events alone, we’ve seen a combined total decrease in home runs by about 11%, a decrease in hits by about 9% and an increase of field outs by 9%. But, what about abandoning all EV/LA combinations and instead looking at league-wide offensive stats? Well, here’s what that looks like:

It seems that, no matter which direction we look, we can see the new ball hard at work. Unfortunately for position players, and maybe even more-so for teams as a whole, that means significantly worse offensive numbers across the board. If this trend continues, we could be looking at one of the worst offensive seasons in MLB history. For example, the 2021 league-wide batting average is currently sitting at .240, which will be the 4th worst all-time if it keeps up like this.

I could be wrong, but I don’t think that’s the sort of change MLB wanted to implement. Instead of making the game faster, more exciting, or whatever their initial goal may have been, they’ve effectively suppressed the entire league’s offense. I fully expect for the ball to be continually tampered with for years to come until they finally land on something that they believe works. But in the meantime, this entire experiment has made the game itself inconsistent, while also making the jobs of the players significantly more difficult.

I feel I should clarify that all of this data and talk of MLB tampering with the ball is purely for educational purposes. This isn’t an excuse to jump onto the “Baseball is dead! The game will never be the same!” bandwagon or anything like that. In fact, this is something that has occurred throughout the games’ history.

This is a game that has been through a Dead-Ball Era, a Steroid Era and several others, all while still managing to entertain and—in some cases—electrify an audience. This game evolves, constantly. It will continue to do so long after we’re here to complain about it. The difference now is that it’s being forced to evolve. Change is much easier to digest when its process is slow, but gradualism isn’t a luxury the fans, players or teams have been afforded in recent years. The only question now is, “Where do we go from here?” That’s a question no one has the answer to yet, but it’s certainly one that will be answered in due time.


All data referenced in this piece is courtesy of BaseballSavant and Baseball-Reference

All charts used in this piece were created by @cardinalsgifs