The High Fastball Isn’t So Scary Anymore

If you’re a major league pitcher right now, there’s a good chance life is pretty smooth. You’ve realized that you can throw more and more sliders without repercussions; it might even be an ideal strategy. You’ve also learned that by using a two-seam grip, you can upgrade a regular slider into a “sweeper,” which is shockingly effective for a pitch that’s so easy to learn. You’ve probably gained a much better understanding of how and why certain pitches do or don’t move. Knowledge is power, especially in baseball, and the modern pitcher is possibly the most educated athlete around.

Meanwhile, there are formerly innovative approaches that you don’t think twice about nowadays – they’ve become the norm. A great example is the high fastball. Back in the days of yore, a perfect fastball meant one located at the knees, down and away. But as pitch data became widely available, teams started to realize that throwing the fastball up would maximize swings and misses and minimize damage on contact. Regular high cheese also served to counteract the so-called fly ball revolution; an uppercut swing made golfing pitches at the bottom of the zone easier but left a hole at the top.

In baseball, what’s exploitable will be exploited. As such, the rate of fastballs up in the zone has continued to climb:

Years after its proliferation, the high fastball is now more popular than ever. That’s partly because of the emphasis on fastballs that have more carry than run, which work best up in the zone. And because teams are targeting this particular fastball shape with zeal, the result is a population surge: There are an increasing number of pitchers, mainly those newer to the big leagues, whose four-seamers need to be located up high. We’ve long talked about existing hurlers making the change, but the influence of rookies can’t be counted out.

Coaxing vertical movement out of developing pitchers and encouraging them to live upstairs has also led to an uptick in whiff rates against high fastballs, even as the number of such pitches climbed alongside it. In 2015, pitchers threw a high fastball 19% of the time, producing a whiff rate of 33%. In 2021, they did so 26.8% of the time, producing a whiff rate of 36.5%. You’d expect this upward trend to have continued this season, with pitchers laughing and looking down at those poor, poor sluggers from their elevated mound. But…

Sorry it took so long to get here. But I don’t think this downturn is nearly as interesting without knowing the context beforehand. This wasn’t supposed to happen. Suddenly, the irrefutable process of adding velocity and movement before taking things up high has come to a halt. Batters are whiffing like it’s 2018, not ’22. It’s a surprise, to be sure, but a welcome one.

Before we proceed, though, let’s fool-proof our findings. Maybe hitters are just having unusually good results against high fastballs early on this season. That sounds unlikely, but no stone should be left unturned. To account for the fact that this season isn’t over yet, I looked at the high fastball whiff rates in April and May of each season in the Statcast era, with the exception of 2020. Here are those numbers put on a graph, along with the full-season rates:

While notable gaps between April/May and full-season numbers do exist (see: early 2017, when batters collectively turned into pumpkins), the story so far remains the same. Even after accounting for the time of year, the fastball whiff rate hasn’t been this low in a while. We can take this a step further by looking at every two-month stretch since 2018:

You can see that whiff rates later on in the season tend not to deviate much from those early on in the season, which bodes well for the idea that this year represents a genuine skid. But if you’re a shrewd reader, you might have noticed the drop-off that occurred between June to July and August to September of last season. Of course, what delineates the two time spans is the enforcement of the sticky stuff ban, which drove down spin rates league-wide. Many pitchers lost their usual fastball zip, resulting in higher rates of contact. If heaters just aren’t as good as they once were, maybe it isn’t so surprising that 2022 is continuing where the previous season left off.

There’s one problem with that assumption, though. As Rob Arthur showed, the league regained most of its lost spin by the end of 2021. We won’t delve into how that happened; what matters is that rather than deteriorate, the league-average four-seamer has become better than ever. A simple comparison makes this crystal clear. Consider how the early fastball whiff rate of 2022 (33.7%) strongly resembles that of ’18 (33.4%). Back then, the average up-in-the-zone fastball sported a velocity of 92.8 mph and 16.1 inches of vertical movement. Fast forward four years, and that average now sits at 93.8 mph and 16.6 inches, respectively. The up-in-the-zone fastballs from August and September of last season aren’t so different in terms of velocity (93.7 mph), but they too fall short in the vertical movement department (16.1 inches).

It might not seem like a huge difference, but according to Cameron Grove’s stuff grader, the representative 2018 high fastball receives a 50 on the 20-80 scale; the representative fastball this season, meanwhile, receives a 58, assuming that other variables like release point and extension remain the same. That’s an increase of nearly one standard deviation. All in all, there’s enough to conclude that hitters are whiffing less despite seeing higher-quality fastballs.

Why might this be the case? One possible reason: They’re better equipped to deal with high heat than in years past. The traditional method of batting practice involves teeing off against pitches that are slow, released from a generic angle, and lacking in movement; that hardly seems like sufficient preparation for a triple-digit heater. Acknowledging this, clubs like the Giants began incorporating machines that replicate spin and velocity during their pre-game routines. Matt Olson, who parlayed a career-best 4.9 WAR last season into a massive contract extension, credits a little red pitching machine for his improved performance against high fastballs. Practice is catching up to the challenges hitters face in games, much to the chagrin of pitchers everywhere.

Or maybe we’ve reached peak high fastball usage – when close to a third of all heaters are located up, perhaps they’ve become too predictable, and therefore easier to make contact against. Interestingly, hitters aren’t laying off of them. The league-wide swing rate against high fastballs remains stagnant and has yet to trend in any direction. They’re still enticing, mind you, but more batters are managing to swipe the cheese without getting caught in the trap. They’ve adapted to life with persistent high heat, and the numbers have just begun to reflect that.

But while we can attribute the rise in high fastball usage to the latest generation of pitchers, we can’t attribute the fall in fastball whiff rate to the latest generation of hitters, at least not yet. A quick search on Baseball Savant reveals that hitters 25 and younger (by season and not real age) are averaging a whiff rate of 34.1% this season. At 33.4%, hitters between 26 and 30 are faring a little better. This is likely because the youngest hitters are more prone to strikeouts in general than those in their baseball prime. But it’s the latest cohort of major league hitters that is arguably more prepared, having experienced the high fastball frenzy in their minor league and even college careers. When these hitters hit their stride, it’s plausible they’ll put up an even lower whiff rate, thereby bringing down the league average.

Besides its capacity to induce a swing-and-miss, there’s an additional, less frequently cited reason for why the high fastball is so potent. A strikeout is an automatic out, but so is a popup – barring a GIF-worthy error, it’s guaranteed to find a glove. And given its typical vertical location and movement, no pitch is better suited to result in the least formidable of fly balls than the high fastball. Currently, it seems like hitters have succeeded in curtailing the whiffs. But if they truly want to stifle the rise in rise, they’ll have to overcome one more hurdle:

This graph shows the rate of popups on high fastballs put into play each season. There has been a gradual decline since 2015, but if you look at this on a monthly basis like we did with whiffs, the present popup rate is within the margin of error. In addition, it’s unclear how to reconcile the Trackman era of Statcast data (pre-2020) with the current Hawk-Eye era of Statcast data. To give you an example, even though the percentage of batted balls hit over 50 degrees spiked dramatically with the introduction of Hawk-Eye, the percentage of popups has largely remained the same, suggesting a shift in classification. That might not be an issue in our specific case, but I’m still hesitant to conclude that hitters are popping up less often against the high fastball.

Thankfully, the book is out on how to square up against high heat. Among the many reasons why a mishit occurs, one is a discordance between the descending angle of a pitch and the ascending angle of a bat. It’s the hitter’s goal to have the two match up, thus maximizing thump and distance. An uppercut swing is the product of a steep bat angle, which is no good against a “flat” fastball at the top of the zone. The solution? An equally flat swing! Ideally, you’d swing up against breaking balls down and down against fastballs up. That’s easier said than done, however. Unless your name is José Ramírez, most hitters have a swing tailored to either the high or low pitch, but not both. It takes an immense amount of skill to hone a fluid, adaptable swing. But as was the case for whiffs, maybe it’s only a matter of time before the mishits dwindle, too.

At one point, the rise of the high fastball symbolized the growing gap between pitchers and hitters. It still does, to a certain extent – a speedy, rising fastball located at the letters will never not be a great pitch. But if there’s a takeaway from all this, it’s that the hitter-pitcher imbalance may be on track to sort itself out. At its core, baseball is a cat-and-mouse game between the hitter and the pitcher, with each trying to gain a fleeting advantage over the other. Right now, it’s the pitchers who stand on high ground. But that doesn’t mean they’ll be in control forever, and maybe that means the league won’t necessarily have to interfere. No intervention or rule changes made the high fastball less of a threat. The players did that all by themselves.

Statistics in this article are through games of June 4.