Breaking Down Baseball’s Early Velocity Surge

Pitchers are scary. I know this because I recently watched an outing by Matt Brash, who, despite his nonexistent command that day, used a scorching heater and two breaking balls to stymie a formidable Astros lineup. He walked six, but those free passes went along with five strikeouts and just two hits allowed. The Mariners won by a score of 7 to 2. So it goes.

Pitchers are scary, and they’re getting scarier, in large part because they’ve developed the ability to throw harder and harder. It probably doesn’t even bear repeating at this point, but because it’s the subject we’re on, let’s refresh ourselves. Back in 2008, the first year with PITCHf/x data, pitchers averaged 91.8 mph on their four-seam fastballs. Last season, they averaged 93.8. That the league as a whole has gained two miles per hour is indicative of substantial change.

It’s 2022 now. It’s early, but so far, pitchers have been averaging 93.9 mph on their fastballs, for an uptick of 0.1 mph. Such a small difference might not seem like much, or something we should focus on right now. But this is merely a cursory glance. We haven’t even separated the starters from the relievers, and it’s the latter group that most people associate with triple-digit wizardry. Are bullpens hiding the fact that rotations aren’t quite stretched out yet due to an abbreviated spring? Let’s find out:

Not surprisingly, relievers have long been ahead of starters velocity-wise. But two trends characterize the more recent years. First, the gap between starters and relievers has shrunk. This season, the standard starter is averaging 93.8 mph, whereas the standard reliever is averaging 93.9. And second, while reliever velocity has essentially stagnated, starting pitcher velocity has been climbing aggressively. Compared to last season, relievers have actually lost 0.3 mph on their four-seamers. Starters, on the other hand, are up by a similar amount: 0.4 mph. Within our established timeframe, it’s the largest year-to-year increase on record.

All hail the illuminating power of graphs. But maybe we are getting a little ahead of ourselves here. It has, after all, been just two weeks since the season kicked off. So in the hopes of not getting yelled at in the comments, here’s another graph. I checked the early-season starter fastball velocities from past seasons and compared them against their eventual, full-season iterations, excluding 2020 due to its shortened slate. If the two numbers are similar, that means we can more confidently put stock into what the first few weeks have demonstrated. Good news:

What starters average early on pretty much mirrors what they record by season’s end. If anything, there’s a tendency for them to pick up a bit of velocity as the summer heat arrives. That could be due to pitchers’ tendencies to ramp up with time, the warming weather, or survivorship bias (bad pitchers don’t normally stay on rosters). Sure, the season started deeper into April than it usually does and the month isn’t even over, but barring unforeseen circumstances, pitchers are indeed on track to shatter a record that has seldom lasted for an extended period of time.

What’s familiar about this year is that once again, there’s been a likely trade-off between effectiveness and longevity. Pitchers are no longer conditioned or expected to go the distance; they’re often built for five, six, occasionally seven max-effort innings, and the numbers bear that out. Fastballs are faster than ever. But starters are also throwing fewer innings than ever, which could help to explain the shrinking divide between them and relievers. Baseball’s innings-per-start ratio of 4.5 as of Monday’s games is the lowest in major league history. That should increase once pitchers emerge from what is essentially an extended spring training necessitated by the lockout, but there’s a good chance they end up undershooting last season’s mark of five innings per start. Whether that’s a good or a bad thing is up to you. The point is, it’s impossible to ignore.

Another similarity: It’s the young guns who are leading the charge. They’ve spent most of their careers in the current age of player development. They’re receptive to data-driven feedback, and importantly, they have considerably less mileage on their arms. It’s no coincidence that starters 25 and younger are averaging a whopping 94.7 mph this season, another record high (remove their contributions, and the league-average velocity drops to 93.4 mph). Some of that, admittedly, is because a player like Hunter Greene has an outsized presence this early in the season (it depends on the data source and what counts as a four-seamer, but if we remove him from the youth cohort, the group’s average four-seam velo dips to about 94.3 mph). But he’s an example of what’s now possible in baseball. Pumpin’ cheese at a hundo has never been so casual.

By comparison, starters who are slightly older (ages 26 to 30) are sitting a full tick lower: 93.7, which is only marginally higher than last season. Now, rookie hurlers do tend to cool off significantly as the season progresses. In 2021, for example, their average velocity in April was 94.4 mph, a mark that stood at 93.8 the rest of the way. But it doesn’t change the overall picture. Many players are throwing harder, and that’s especially true of the latest generation.

These are new pitchers we’re talking about, pitchers who had previously never made an impact at the major league level. But also contributing to higher velocities are pitchers with a few seasons under their belt, pitchers who used the offseason to become better versions of themselves. Maybe this is where we can identify how this season’s surge is different compared to previous ones. I thought of Alex Cobb, who in his first start for the Giants topped out at 96 mph – something he’d never accomplished before. Might we be seeing more velocity gains from older starters, and can we show that?

Cobb won’t be included in the rest of this article because I’m focusing on four-seamers, but that’s fine – there are plenty of other pitchers to work with. So far in 2022, 68 starting pitchers have thrown at least 50 four-seam fastballs. Looking back to 2021 data, I worked out each pitcher’s change in velocity and selected players who added more than 0.5 miles per hour. It’s an arbitrary threshold, but bear with me. I’ve also included their respective ages (as defined by the baseball season, not real life):

It’s unclear to me whether this is consistent with earlier seasons. But here, at least, the vast majority of starters who have added significant fastball velocity are in their mid- to late-20s. Darvish seems to be the outlier, and so is Cobb if we’re looking at sinkerballers. Teams have become adept at tailoring their development programs to individual pitchers’ needs and strengths, but physiological limitations are real: Past a certain age, access to new velocity heights or even former glory requires a perfect storm, and maintenance is another challenge on top of that. Why might the pitchers listed be of a similar age? Because it’s an opportune moment for more permanent changes.

All in all, this year’s velocity surge is a continuation rather than a deviation from any norm. While the relievers remain stuck, the starters are catching up at an alarming pace. And among those starters, the youngest ones are pushing the envelope with new, never-seen-before speeds, while those who are slightly older are building upon what they carried into the big leagues. There’s not much movement past the age of 30, but success stories certainly exist; in the future, they could become more common. I did notice that starters 35 and up are throwing much, much harder than in years past, though that’s because there are so few of them to begin with, and the ones who have stuck around are at this point in their careers precisely because the gas never stopped.

As mentioned before, this analysis leaves out pitchers whose primary fastball is either a sinker or a cutter. But in case you’re curious: For relievers, the average sinker velocity is up by 0.2 mph, while average cutter velocity is up by just 0.1 mph. In the case of starters, the average sinker velocity is down by 0.1 mph. Surprisingly, the average cutter velocity has jumped from 88.1 to 88.8 mph, but I’m willing to diagnose that as a residual effect of peppering in cutters once in a while as opposed to a genuine rise in cutter-first starting pitchers. It’s worth bringing up though, since, well, that uptick encapsulates what’s so stunning (and terrifying) about modern pitching. For a moment, we thought we might have reached a plateau. Soon afterwards, league-wide velocity began to trend upwards again, and here we are. It’s hard to say there even is a limit.