Picture the following: One random day, you open your eyes and find yourself in a big-league bullpen with no recollection of who you are or why you're here. Just as you're beginning to register your surroundings and the uniform and glove you're wearing, a coach -- or someone who looks like one -- strolls up to you with what looks like some sort of tablet in hand. With a calmness and familiarity that exists in stark contrast to your confusion and bewilderment, he speaks to you like you're old pals.
"Can we get a catcher here, please?" he voices to no one in particular -- at least no one you can see. "Alright man, ready to get started?" he adds.
"Uh... sure, sure," you reply, uncertain of what he expects out of you. Out of the corner of your eye, you see someone sporting some sort of protective gear, mask and everything. It all looks oddly familiar to you. It must be, since your coach goes along with the process as though you've done this a million times.
"Alright, then. Give me a heater to kick things off, then we can go from there," your coach suggests, putting a baseball in your glove.
For some reason, the second you grab the baseball and toe the rubber on a set position, things start falling into place and your next movements become second nature. Looking into the target your catcher is kindly setting for you, you lift your lead leg, knee bent at an angle, and begin to drift. You let your momentum -- and a violent snap of your hips and torso -- do the job and the white ball comes out of your hand like a bullet, a deafening sound rattling throughout the facility as it reaches your partner's mitt.
You hear your coach hum with what sounds like appreciation as he looks into the tablet. "Pretty nice for the first one. Pure backspin, as always," he comments, turning the device so it faces you. Among the many numbers you see on the screen, a few catch your eye.
A vague idea of what those numbers mean crosses your mind, but you're not quite sure -- your memory still seems a bit foggy. Worry not, though, because we're here to refresh your memory and get a better understanding of the kind of pitcher you are. Along the way, we'll examine your pros and cons, what makes you unique, and the different paths you can follow.
Setting aside any existential questions one might have after waking up in a place they're not familiar with, we can get to answering baseball questions instead. First things first, though: Those numbers we saw, what do they mean? Velocity and raw spin rate are straightforward, of course, but what about the rest?
The spin axis refers to the direction the ball spins in, expressed in the form of a clock. In this case, 12:30 means that if we had to draw a line to reflect spin direction through the middle of the ball, that line would be at an angle that coincides with that time. 12:30 is a pretty vertical axis, making it likely that we're dealing with a pitcher who throws out a fairly high slot. There's a direct and logical correlation between spin axis and arm slot, of course; sidearm pitchers tend to spin their pitches near the 3 o'clock range, for instance.
In simple terms, spin efficiency (also known as active spin) is the percentage of a baseball's total spin rate that contributes to its movement. In this fastball's case, then, 99% of those 2300 rpm are weaponized to create movement. This is just about as high as a human being can get on the spin efficiency spectrum -- when paired with that 12:30 axis, we're looking at a pitch being thrown with near perfect backspin.
IVB stands for Induced Vertical Break. It's measured in inches and refers to how much spin-induced vertical movement a particular pitch has, both in positive and negative values. The easiest way to think about this for me is the following:
Coming back to our example, 19 inches of IVB is excellent. Of the 559 pitchers to toss at least 50 four-seam fastballs in 2024, only 22 averaged 19 inches of IVB or higher. For reference, the major-league median for IVB on a four-seamer is typically around 15-16 inches. Anything above 18 is quite good, and by the same token, anything below 14 is quite flat. IVB is far from the only thing that matters in a fastball, but that's a topic for another day.
All these data points we've been looking at are very strong indicators that, when combined, point us towards a particular conclusion: this pitcher we're dealing with is extremely likely to have a tendency towards getting behind the baseball at release, in contrast to pronation bias (getting on the inside of the ball) and supination bias (getting on the outside of the ball). Backspin-dominant pitchers feature extreme spin efficiency, good IVB numbers, and almost always throw from fairly high slots that enable them to weaponize their feel for this kind of spin. This means high release points, which are closely related to IVB:
The Y axis is a pitcher's vertical release point, the X axis is the IVB for each pitcher (min. 50 four-seamers in 2024). You can see just how obvious the correlation is, and for good reason-if you want the baseball to have immaculate backspin and as such tons of IVB, the best way to accomplish this is through a high slot, which enables you to backspin the ball on a more vertical plane. Lower slots, with their sideways spin, are more frequently associated with run rather than carry.
This is what a good carry fastball often looks like, courtesy of Red Sox reliever Justin Slaten:
If you've watched baseball at all over the past seven or eight years, you'll be familiar with this sight. High fastballs became all the rage as teams hunted for strikeouts, their prowess perfectly designed to take advantage of a generation of hitters geared for low-ball hitting. While the carry fastball is not as prominent in the heater discussion as it was three years ago, as sinkers and cutters have regained some of their prominence, it remains a defining archetype of the modern game. But what does this kind of fastball mean for, and what does it tell us about a pitcher who throws it?
Let's look at the good stuff first. Being a backspin-dominant pitcher in possession of a carry fastball has a certain set of undeniable advantages that make up the core identity of these hurlers; there's a reason this archetype has been around for so long and experienced so much success.
The first and most obvious luxury a carry fastball affords you is the ability to miss bats with your heater, as batters will often swing underneath a ball that seems to ward off the pull of gravity more than it should. The importance of this trait cannot be understated. A fastball capable of creating swing-and-miss makes every other pitch in an arsenal play up and provides the pitcher with an enviable level of versatility (and platoon resistance) in terms of approach. Being able to attack at different levels and have batters come up empty at different speeds is a crucial tool to have, and pitchers with rising fastballs who pepper the upper third of the zone have a natural advantage in this area.
Another byproduct of a well-located carry fastball is the inevitable stream of poor flyball contact the pitch tends to generate. Even when a batter avoids a full whiff, they'll often get under the ball on contact, resulting in plenty of lazy flyballs and, when the fastball is great, tons of pop-ups as well. All this airborne contact means pitchers with dominant carry fastballs have a natural tendency to allow fewer hits than more neutral or groundball-oriented pitchers. The combination of good control and a dominant rising fastball has been the catalyst of many fantastic baserunner-suppressing seasons we've seen from the likes of Justin Verlander, Robin Roberts, Sandy Koufax, Catfish Hunter, and so on. Some of you will remember Matt Cain's defiance of the DIPS theory, for instance: a perfect example of this idea.
The way a backspin-oriented pitcher's fastball will dominate the upper third of the zone provides excellent opportunities for tunneling, especially with breaking balls of vertical shape such as 12-6 curveballs and bullet sliders (picture Dylan Cease or Tyler Glasnow). Even offspeed pitches such as splitters apply here. Thanks to their fairly high slots, pitchers with explosive fastballs are often natural fits for overhand curveballs, and many excel at creating both positive IVB for the heater and negative IVB for the hook.
This kind of north-south plan of attack naturally lends itself to more swings and misses than the traditional east-west approach seen in sinkerballers. In a league where damage on contact is extreme and virtually every spot in a lineup is occupied by hitters who can hit the ball out 10-15 times a year at worst, punchouts are incredibly important, and backspin-dominant pitchers have the upper hand in getting them.
Of course, nothing is perfect, and pitchers with backspin bias are no exception to the rule. While they possess many relevant advantages relative to other hurlers, they also face certain cons that others may not.
We mentioned the advantages of being a flyball pitcher before, but there's also disadvantages, the most obvious of which being a natural propensity to home runs. Many of those same legendary pitchers we named also shared the unfortunate weakness of giving up dingers here and there, a logical consequence of working a carry fastball up in the zone. These kinds of pitchers can be prone to hard contact from time to time and often lack the tools others have to keep damage in check. Sinkerballers, for instance, can wipe out some of their baserunners on double plays and be sure that most of the hard contact they allow will be on the ground, but backspin-dominant pitchers don't have that luxury.
While backspin is a great thing for a fastball, it can be a problem when crafting secondary offerings. Changeups are the most obvious potential obstacle, as it's not uncommon to see pitchers with dominant carry fastballs struggle to take power and lift off the ball on their cambio because their tendency to get behind the ball is too strong. This doesn't mean changeup development is impossible -- far from it -- but it can be bumpy at times and is usually far from the natural process it would be for someone who excels in pronation. This is also why these pitchers are such good candidates for splitters, since their low-spin nature can help remove this issue altogether.
Similarly, backspin-dominant hurlers can sometimes struggle with creating depth on harder breaking balls; it's common for these kinds of pitchers to end up with cutter-slider hybrids rather than true sliders because they get behind the ball too much. Another problem worth mentioning is the limitations these hurlers face in terms of their plan of attack. Those huge sweeping sliders teams love can be an awkward fit in a vertically-oriented repertoire, making the pitcher's arsenal streamlined in a predictable way.
In line with the previous point, backspin-biased hurlers are not famed for their fastball variety, often throwing only a four-seamer. This is out of necessity. Pronators can run it, sink it, and even carry it on occasion. Supinators are naturally positioned to cut it and sink it, and like pronators, can also pitch upstairs when needed. Backspin-dominant pitchers, though? They can carry the ball, of course, but not sink it -- they get behind the ball too much to create depth. They can cut it at times, but that often comes in the form of a slider-cutter hybrid instead of a true cut fastball. And they always run the risk of the cutter blending into the fastball and making both pitches worse.
Having multiple quality fastballs is a good thing: It allows a pitcher to challenge batters of differing handedness, swing path, and so on, not to mention the strategic boost of having multiple hard pitches that move in different directions. If, as is the case for most pitchers with carry fastballs, you only have one type of heater, you can become easier to predict. This obviously doesn't spell doom, but it's yet another example of why these kinds of pitchers really need to be capable of overpowering their opponents in order to succeed.
Why the title "The Gift & The Curse"? Simply put, while every pitcher has their repertoire dictated to certain extent by their natural tendencies, no group is as binary as these guys. They reap huge benefits and see huge limitations, both coming as part of a package deal. On one hand, no other pitcher archetype is as predisposed to striking batters out as backspin-dominant pitchers, who possess a fastball capable of missing bats and the kind of vertical attack that leads to the most whiffs. On the other, their relative lack of variety and propensity for allowing flyball contact can leave them vulnerable to damage.
A crucial part of this kind of pitcher's success, then, is the development of some sort of secondary pitch that allows him to control damage to a certain extent. This is especially true if we're dealing with a hurler without overwhelming velocity. As mentioned, splitters and cutters are nice choices in this regard, but don't be fooled -- a pitcher with a carry fastball must be able to overwhelm his opponents in some way, being reliant on strikeouts in a way others aren't.
So much of the success of this archetype lies in the delicate equation between home runs and baserunners. It is key that these pitchers limit their inevitable home runs to be solo shots, whether that be via outlier strikeout rates or a mix of hit and walk suppression. It's a fine line to balance on. Justin Verlander's Astros peak between 2018-21 is perhaps the ultimate example of this idea -- in fact, Verlander represents the archetype as well as any pitcher ever has, down to his nightmarish 2024, when his strikeout rate has fallen and the damage on contact has been too much to bear. He can't escape his nature.
When I talked about pronation early in 2024, I mentioned how variety is part of the secret sauce that makes baseball so special, and how even during a sweeper-crazed time, changeup artists remain highly effective. This applies to backspin-dominant pitchers too. The high fastball is no longer the fad of choice, but it remains a huge part of the game, and no one does it like these guys: the tightrope-walking, high fastball-slingin' pitchers who help make our game beautiful.