Recent trends in baseball are measurable and irrefutable. Strikeouts and home runs keep going up. Batting averages and the raw number of balls put into play keep going down. Scoring levels mostly have been fine, but generating those runs has become increasingly dependent on the long ball.
That much is clear. What's less clear is the perception of those facts. To some, the reliance on home runs on offense and strikeouts on defense leaves too many periods of relative inaction. Not everyone agrees. However, the powers that be in baseball have sent the message that they are part of the former group. They send the message with every announcement regarding a rules experiment. And they sent the message before the season by changing the ball.
Ever since news about the tweaks to the ball emerged -- in the form of a leaked memo obtained by The Athletic -- MLB guaranteed that scrutiny on that little piece of equipment would be a major aspect of the 2021 season. The memo was full of physics jargon, but the gist was that the ball would be a little lighter (by 2.8 grams) and would a fly little less far (by 1 to 2 feet on average). Sounds simple and even unobtrusive, but we have learned over the years that even microscopic variations in the performance of the ball can have an outsize impact on the game.
The primary goal of the changes, as reportedly outlined in the memo, was to make the performance of the ball more consistent from batch to batch and season to season. That makes sense, but it also makes sense that baseball would want the revised specifications to start us down the road to a more balanced product, where contact hitting and stolen bases regain some footing when compared to the prevalence of homers and strikeouts.
We're six weeks into the season and have seen some extreme numbers. We might be on track for the lowest aggregate batting average in the history of baseball. At the same time, scoring -- you know, that thing that determines who wins the game -- is down from the past couple of seasons, but remains unremarkable in the context of recent baseball history.
Is the new ball helping? Is it making things worse? Is it doing anything at all?
Let's try to answer those questions.
Home runs are alive and well
When you talk about the performance of the ball, the focus usually is on the home run count. The five seasons with the highest rates of homers per nine innings have been the past five seasons. In 2019, the record for that metric was established at a stunning 1.4 home runs for every nine innings played. Last year, the pandemic season that played out exclusively during the warm-weather months, saw 1.34 HR/9.
So how are we doing this year with the new ball? Through Sunday's games, baseball's rate of homers per nine innings was 1.16. That's less than last year and even more less than the record season of 2019. Alas, there is much more to the story than that.
First, as we know, it's still early spring. It's colder than it will be in the months ahead, and baseballs don't fly as far in the cold. This isn't just a trope -- it's a verifiable thing. Based on recent trends, we can expect the homer rate to increase anywhere from 5% to 10% over the course of the season. The degree of the rise varies from season to season, but if you factor in a typical increase, we can expect to end up at around 1.25 homers per nine innings.
That rate of homers is still lower than it has been the past two years. But nevertheless, that figure would challenge 2017 for the third-highest homer rate in baseball history. We're not exactly talking about a dead ball here. OK, great. It was a worthy attempt, MLB. We still need to shave a few more ticks off that homer rate, so let's just deaden the ball a little more. Try, try again, or something like that.
The problem is, it's unclear just how much of the still-strong homer rate is because of the ball and how much is because of evolving approaches by both hitters and pitchers. And problem is the appropriate word here, because sifting through the statistical evidence is to convince a humble analyst he has wandered into a land of infinite paradox.
Here's the first paradox you run into. The increase on home run reliance is a thing. Since 1974, 33.8% of runs have scored via the homer. That number reached the 40% threshold in 2016 and has remained above it since, peaking at 45.2% in 2019. So far this season, it's at 41.2% and, given the coming uptick in homers with the change in weather, we can project that it'll end up at around 43.6% by the end of the season.
That trend was in place before the new ball, but what may have changed is how the R/HR% metric correlates with run scoring. The top five teams so far this season in terms of runs/HR% are the Braves, Cardinals, Giants, Yankees and Indians. The highest ranking among them in runs per game is the Braves, at No. 9. Of the five highest-scoring teams so far -- the Reds, Astros, Red Sox, Dodgers and White Sox -- Cincinnati ranks the highest in R/HR%, at No. 15. Of that quintet, only the Dodgers rank outside of the top five in batting average. It's not that the high-scoring teams don't hit homers. They do. But they are currently elite on offense because they do other things as well.
There is, in fact, a slight negative correlation this season between R/HR% and runs per game, though that should change somewhat with the coming weather-related increase in homers. Nevertheless, there will still be mixed signals coming from the team leaderboards. At the league level, teams remain as reliant on homers to score as at any point in baseball history. But the relationship between that team trait and scoring seems less straightforward than it has in past years.
Despite this, teams continue to develop and choose their players with a preference for home run hitting at the forefront. Perhaps the best place to see this is in Statcast-generated metrics. Here is where the terms reside that many baseball purists have come to dread: exit velocity, launch angle and the unholy offspring of those two metrics -- the barrel.
So far this season, teams have produced an aggregate rate of barrels per batted ball event of 8.2%, up from 7.6% last season. This has been a number that's gone up annually over the past few years, since Statcast data was revealed to the public during the middle of the last decade. For reasons that are unclear, this is another number that evolves over the course of a season, but we should still see another high-water mark for barrel rate of somewhere around 8%.
The average exit velocity on barrels this season has been 105.1 mph, which is a marked increase over the past few seasons and the highest mark of the Statcast era. In a different way, physics-savvy Baseball Prospectus author Rob Arthur delved into this weird dynamic. He found that the new, lighter baseball appears to be bouncier -- i.e., it ricochets off the bat with more ferocity -- but it loses steam in the air.
All of this is roughly what MLB said would happen. And it has. Despite the increase in the frequency of barrels and the rise in exit velocity when they occur, the rate of homers on barrels is down. So far, 49% of barreled balls have left the yard, down from 56.1% in 2020 and 59.4% in 2018. Alas, this is yet another number that will evolve, and we can project that it'll end up at around 53% by the end of the season. That number would still be lower than any season between 2015 and 2020.
Still, the raw total of homers isn't likely to go down that much, if at all, because batters have increasingly adopted all-out home run approaches. If the decrease in homers per barreled ball proves to be lasting, it's offset because there are more barrels overall. Nevertheless, the apparent disconnect between scoring and homer reliance -- if it is real -- could mean that we are looking at a landscape with multiple incentives for teams to fashion offenses that do more than hit the ball out of the park. That is, you need offenses that do more than hit homers to be elite, and the returns on balls flying through the air are diminishing, if only a little.
What might really prove to be a tipping point would be if the new bouncy-but-less-flighty ball was leading to a renaissance in ball-in-play indicators.
Alas ...
What the hell happened to balls in play?
Recent narratives about depressed offense are only partly true. As mentioned, run scoring remains unremarkable. Yes, it is down from the past two years. So far in 2021, we've seen 4.48 runs per nine innings, down from 4.86 last season and 4.85 in 2019. However, the five-year average between 2015 and 2019 was 4.57. The 10-year average, ending in 2019, was 4.42. The 15-year mark was 4.53. The 52-year mark (the divisional era) is 4.48. That's why we say that 2021 scoring has been unremarkable.
Nevertheless, it is remarkable that the MLB batting average is currently .236, and that's actually an increase from the .232 mark at the end of April. Like home run rates, averages go up as the weather warms, but given normal patterns, baseball can at best hope to barely top .240 by the end of the season. The only seasons during the modern era in which the aggregate average was under .240 were 1908 (.239) and 1968 (.237). And both of those seasons did not benefit from the utilization of designated hitters in at least one of the leagues.
Batting average is a function of two things: How often you put the ball into play and how often it ends up as a hit when you do. Both functions are on the fritz in contemporary baseball.
The rate of balls in play is the inverse way of looking at strikeouts. This season, the strikeout rate is on track to end up in the neighborhood of 24%. That would, once again, set a record. None of this is news. What would be news is if the new ball was contributing to this rise.
That is a little hard to ascertain. As with a lot of these 2021 trends, you can make a case that the ball is a driving factor. But most of them can also be explained by typical year-over-year variation, the rate of trends that were already in place, or both. That's especially true of strikeouts.
There are some data points that seem noteworthy. Pitcher velocity is up, and that could be in part because of the lighter ball, but probably not. The average velocity of four-seam fastballs this year is 93.5 mph, up from 93.3 last season, according to TruMedia. That seems stark but when you look at individual pitchers, the story becomes murky. You'd expect that if the ball itself explained the rise in velocity that most pitchers would see the improvement. But it's more a 50-50 proposition.
Spin rate is also up, both on four-seamers and on breaking pitches. There has been some chatter that the laces on the new ball are slightly more prominent, or at least more consistently prominent than they were in past seasons. This might explain the uptick in spin rate, or it might simply be explained by the fact that it's been going up every year.
There is one aspect of pitch behavior that seems like it could fall a bit outside the boundaries of normal year-to-year variation. This is the Statcast measure of vertical break.
We'll focus on four-seamers to illustrate this. For pitchers, the closer to zero this number is, the better. In other words, all pitches drop because of gravity, but the best four-seamers drop less than the average four-seamer. That's what created the optical illusion we call a "hop." Since the start of the 2018 season, the pitchers with the best vertical break metrics on four-seamers have been Justin Verlander, Blake Snell, Walker Buehler and Gerrit Cole. Pretty good pitchers, right? Their rates of vertical break are strong because their spin rate is high, keeping the ball up in the zone longer, and they get more swinging strikes as a result.
According to TruMedia, from 2018 to 2020, the aggregate vertical break on four-seamers was highly stable, at around 16 inches. Thus far this season, it's at 14.8 inches. With that, the rate of swinging strikes on four-seamers has increased, from 10.4 to 11. Again, is this the ball, or just the product of trends that were in place already? If the ball is lighter and the seams are higher, it could be both. This is something baseball will have to investigate, because this isn't the direction you imagine they wanted things to head when the specifications for the ball were determined.
OK, so the ball may or may not be contributing to the unfettered rise in strikeouts and decrease of balls in play. But what about when the ball does enter the field of play? How are we doing there?
Not good. Not good at all, and this may be the most troubling metric in baseball right now, outside of the strikeout rate. The average on balls in play in baseball so far this season is .286. If that number were to hold, it would be the lowest figure since 1992. This is another statistic that will increase as the weather warms, but even so, we're headed toward a BABIP within a point or two of .290.
What makes this figure so important is that if we want teams to adopt strategies in team building and offensive approach that are less homer-centric, we need to incentivize them to do that. One way is to make home run hitting a dicier strategy, which cutting into the flight of the ball would eventually accomplish. As we've seen already, that part of it is a work in progress.
The other incentive is to make hitting the ball in play a profitable endeavor. Between 1993 and 2017, the aggregate BABIP operated in a narrow band between .293 and .301, and usually landed in the .299 or .300 range. It fell to .295 in 2018, recovered to .298 in 2019, then plummeted to .292 in 2020. That was the weird season but unfortunately, that bit of weirdness seems to have carried over, new ball or not.
Some of it is quality of contact but that doesn't explain everything. The BABIP on barrels is usually well over .500. So far this season, it's at .462. Even with a normal weather-related recovery, a reasonable guess of where it'll end up is .501. That's down from .524 last year and .525 in 2019. Barrels are by definition balls with a high quality of contact, and they are not performing as well this season.
You see a smaller dip on non-barreled balls, which are about 10 times more common that the barreled ones. The problem is that if you are changing the ball to cut into its carry in the air, i.e., to put a dent in the homer rate, you want to do it in a way that improves its performance in other ways, or at least doesn't inhibit it. You don't want even a small dip in non-barrel BABIP. You want a rise. That's not happening.
One minor force driving down BABIP is quality of contact outside of the realm of those sweet barreled balls. Basically, we're getting more fly balls on contact than last year and the main bucket the extra flies are coming from is that of line drives. BABIP on flies is actually up a little, but that is a small thing. Most fly balls either end up as homers or outs.
More important is the drop in frequency of line drives, as that accelerates the drop in BABIP. Why? Because average on line drives is, as you would expect, exceptionally high. That figure so far in 2021 is .620, which is a representative number for recent seasons. The frequency of line drives -- as a portion of balls in play -- is down by nearly 5% over last season. How or if the dip in line drives relates to the ball is unclear. It is possible that all of those four-seamers that are staying up in the zone longer are playing into this, but that's a bit hard to pin down at this juncture.
A more significant factor in the BABIP drop is almost certainly not highly correlated to changes in the ball. That would be average on ground balls, which so far is an abysmal .228. Last season it was just .227, but before that, it tended to range from the high-.230s to the mid-.240s.
What happened? The most likely explanation is that teams have just gotten better at aligning their defense. It's not just shifting, but also knowing better when not to shift, as is often the case with right-handed batters. There may also be a quality of contact issue in play that is an offshoot of the recent emphasis on getting balls into the air. You see that in a decrease in the average launch angle of a grounder, which you can think of as an increase in balls that are topped or chopped into the ground rather than struck sharply. Such balls have a much lower BABIP than balls hit a more favorable angle.
Try, try again
Let's review:
The ball may not be flying as far, but for a number of reasons, the difference isn't stark enough to put a meaningful dent in the home run total.
If the ball is having an impact on strikeouts in the form of movement and spin, it's not the impact you'd want if you're trying to get more balls in play.
If the aim is to generate more balls in play, the incentive to do so is increasingly undermined by worsening results when players do just that.
At the bottom line, baseball has a heck of a riddle to solve. That doesn't mean that it should quit trying. The game needs to keep pushing even though things could get a whole lot worse while it makes the effort. Imagine what it looks like if the current rate of contact was combined with the current trend of decreasing BABIP and a sudden dive in home run rate. Hope you like your 1-0 games.
Even if that were to happen, the painful transition period would be worth it, and for hope, you look to individual players. Yes, making contact is harder than ever. But you still have a smattering of contact artists, including bat control wizard Nick Madrigal, who wouldn't look out of place on the Hitless Wonder White Sox of the 1900s, and Luis Arraez, David Fletcher, the criminally underrated Michael Brantley, Whit Merrifield. It can be done.
You have too many players who seem to be all about take and rake, and want to launch and pull everything. But you also have the majesty of a Mike Trout or a Juan Soto or a Ronald Acuna Jr. or a Mookie Betts, who seem impervious to all the trends that make us pace the floors at night. Such stars are avatars of what baseball is at its best -- and prime examples for amateur players of how to play the game in its more ideal form.
The kind of baseball so many of us fell in love with is still there to be found in the form of these Platonian ideals of a hitter. And all these trends? They are the stuff we talk about between games, but not during them, when we're rooting for our favorite team to win.
The best news is that with its willingness to adapt and experiment, the caretakers of baseball have shown they are actively trying to figure out how to make the greatest game the best version of itself. The on-field product we've seen in 2021 might not be it, but it's been plenty good. Imagine what it'll look like when MLB finally figures out how to put the game back into balance.