Hitting a baseball is an unthinkable accomplishment of timing. In order to strike a ball traveling from the pitcher’s hand to the plate in less than half a second with a slab of wood, a hitter must execute an elaborate sequence of movements on time. When do you lift your front foot? When do you load your hands? When do you fire your hips? It’s a sophisticated choreography; a beat late at any point can doom the swing.

Picture Fernando Tatis Jr. When Tatis is at the plate, he shifts around like a predator stalking its prey, eyes peeled for the exact moment when the pitcher lifts his front foot so that he, too, can get his toe down at the right time, and then his hands up, and then finally the barrel through the zone:

If hitting is such a delicate sequence, conditional on the pitcher’s own timing, it follows that pitchers who mess with that timing can improve their performance; by extension, pitchers who groove their deliveries will underperform their stuff. In an interview with David Laurila in 2017, Jason Hammel described changing his delivery for these precise reasons. Read the rest of this entry »

I thought I had it sorted out; it took one batted ball to convince me otherwise. It was the bottom of the seventh inning during the Rays’ first game in their new George M. Steinbrenner (GMS) Field digs. Jonathan Aranda worked his way into a 2-0 count against Rockies reliever Tyler Kinley. With runners on second and third, one out, and the Rays down two runs, Kinley hung a slider. Aranda uncorked his A swing, launching the ball deep to right field. Off the bat, I thought it looked way gone. It didn’t even go 300 feet:

Read the rest of this entry »

For the Tampa Bay Rays, it was the fearsome power of nature; for the Athletics, the whims of a greedy doofus. But while the cause may vary, the outcome is the same: Both teams will play all 81 of their home games this season in minor league parks. The A’s will set up shop at Sutter Health Park, also known as the home of the Triple-A River Cats; the Rays’ address is now George M. Steinbrenner (GMS) Field, the erstwhile environs of the Single-A Tampa Tarpons. (The River Cats will share custody, while the Tarpons will move to a nearby backfield.)

This is suboptimal and sort of embarrassing for the league. But it does present a compelling research question: How will these parks play? According to the three-year rolling Statcast park factors, the Oakland Coliseum and Tropicana Field both qualified as pitcher-friendly. The Coliseum ranked as the sixth-most pitcher-friendly park, suppressing offense 3% relative to league average, while Tropicana ranked as the third most, suppressing offense around 8%. Where will Sutter Health and GMS Field settle in?

I started by looking at how each park played in their previous minor league season. Over at Baseball America, Matt Eddy calculated the run-scoring environment for each ballpark in the 11 full-season minor leagues. Eddy found that Sutter Health ranked as the most pitcher-friendly Pacific Coast League park by far in 2024, allowing 31% fewer runs than the average PCL park. GMS Field played closer to neutral compared to its Florida State League peers, but it did significantly boost home runs, particularly to left-handed hitters. Read the rest of this entry »

After wrapping up our position player rankings last week, we turn our attention to the league’s pitchers, starting with the bullpens in the bottom half of the reliever rankings.

It’s impossible to project relievers. The pitchers themselves are random enough, sprouting new pitches or gaining five ticks on their fastball with no prior warning. Pitchers also tend to get injured, especially the ones who go max effort on every pitch. And then there’s the randomness of 60-inning samples, where a fly ball sneaking just past the glove of a leaping outfielder can catapult an ERA from respectable to disastrous. This is all to say that the task of forecasting a bullpen’s performance over the course of a single year is destined to fail.

So I’ll take this introduction as an opportunity to encourage you to not take the order of these rankings too seriously. Less than one-tenth of a win separates some of these teams. There is perhaps just one truly terrible bullpen in the mix; every other team essentially has a mix of proven shutdown guys, solid middle-inning depth, and intriguing wild cards. With that said: To the rankings! Read the rest of this entry »

I’m not much of a YouTube guy or, really, a fan of videos in general. If you send me an Instagram reel, I’m sorry, I will not watch it. But Lance Brozdowski delivers his baseball thoughts in video form, so I am compelled to make an exception. Lance’s posts prodded me to start writing about baseball in the first place; I always learn something when I watch his stuff and tend to agree with all of his analysis.

So I was shocked — shocked! — to hear him express pessimism about Spencer Schwellenbach in a recent video. All through this offseason, I’ve had the opposite thought: There isn’t enough enthusiasm about Schwellenbach’s rookie campaign, during which he posted a 3.29 FIP over 123.2 innings. But Lance wasn’t the only one with a tepid appreciation for the right-hander. Eno Sarris ranked him as his 34th-best starting pitcher; Thomas Nestico had him at no. 36. If I were obliged to make such a list, I might be pushing him some 20 spots higher. I think Schwellenbach’s rookie excellence can be repeated and even improved upon for one key reason: When he delivers the baseball, nobody knows what to expect. Read the rest of this entry »

There isn’t much for a baseball writer in the dull days of late February. Someone added a new pitch? The pitching nerds are all over it. Somebody else set a new career high for exit velocity? I’m not sure that merits more than a tweet and/or skeet. Statistically responsible baseball writers have long concluded that attempting to find signal in the noise of spring training stats is a futile exercise.

Thankfully, Effectively Wild came to my rescue. On Episode 2288, Ben and Meg discussed the peculiar case of Justin Verlander, who is pitching in the Cactus League for the first time in his career. After allowing a home run off a hanging slider, he sought consolation from his new teammate, Logan Webb.

“I was told not to overconcern yourself with pitch shapes here and the movement of the ball because it’s tough,” Verlander told Maria Guardado of MLB.com after his start. “It’s my first spring training in Arizona, so everyone was like, ‘Hey man, it’s a little different out here.’ I’ve heard it from everyone. But I think you still need to be honest with yourself.” Read the rest of this entry »

Nobody wants to throw a backup slider. They are, definitionally, an accident. But announcers and analysts alike have noted that these unintentional inside sliders — perhaps due to their surprise factor — tend not to get hit. In 2021, Owen McGrattan found that backup sliders, defined as sliders thrown inside and toward the middle of the strike zone, perform surprisingly well.

I’ll add one additional reason these pitches are effective: They move more than any other slider.

I analyzed over 33,000 sweepers thrown by right-handed pitchers in the 2024 season. I found a clear linear relationship between the horizontal release angle of a sweeper and the horizontal acceleration, better understood as the break of the pitch. On average, as the horizontal release angle points further toward the pitcher’s arm side, the pitch is thrown with more horizontal movement.

Josh Hejka, a pitcher in the Philadelphia Phillies minor league system, told me these results corresponded with his anecdotal experience.

“I’ve often noticed — whether in game or in the bullpen — that the sliders I throw arm side tend to actually have the best shape,” Hejka said. “I believe it’s conventional wisdom across baseball that the backup sliders tend to actually be the nastiest.”

Check out all the movement Corbin Burnes gets on this backup slider from last season.

The relationship between horizontal release angle and movement also holds true for sinkers. When a sinker is aimed further to the glove side — for pitchers facing same-handed hitters, this would be a backdoor sinker — the pitch gets, on average, more horizontal movement, as is the case with this pitch from Anthony Bender.

The explanation for the relationship is straightforward enough. When sweepers are thrown to the arm side and sinkers are thrown to the glove side, the pitcher’s grip is such that maximum force is applied to the side of the baseball, allowing for more sidespin. In a 2015 interview with David Laurila, then-Royals pitching coach Dave Eiland described why sliders back up.

“They really get around it; they don’t get over the top and pull down,” Eiland said. “It’s unintentional, more of a misfire, so to speak. If you could do that intentionally, you’d have a decent pitch.”

It isn’t just sweepers and sinkers that show a relationship between release angles and movement. Back in August, I investigated the mystery of the invisible fastball. Why was a pitch like Shota Imanaga’s fastball, with its elite vertical movement and flat approach angle, so rare? I found that vertical release angles mediate the relationship between both variables. A fastball thrown with a flatter release angle gets less backspin, and so to achieve both requires outlier mechanical skills.

Release angles don’t just measure the nature of a grip, they also dictate the location of the pitch. I conclude that where the pitcher aims a pitch changes the way it moves. For fastballs, pulling down on the ball allows for more backspin. For sweepers and sinkers, getting around the ball allows for more sidespin. Analysts attempt to separate “stuff” from “location;” these findings complicate that conversation.

***

Before we go any further, it’s important to know what exactly is a release angle. Release angles measure — or, in this case, approximate — the angle at which the ball comes out of the pitcher’s hand. For vertical release angles, anything above zero degrees suggests the ball is pointing upward at release; most vertical release angles, particularly for four-seam fastballs, are negative, meaning that the pitcher is aiming the ball downward at release.

Horizontal angles work the same way, but in the x-dimension. Positive values mean the ball is pointed toward the pitcher’s left; negative values point toward the pitcher’s right. (This is a feature of the original Pitch F/X coordinate system, when it was determined that x-dimension pointed to the catcher’s right.) In any case, release angles, both horizontal and vertical, attempt to capture the exact position of the ball at release. Because they capture the position of the ball at release, they contain information about the pitcher’s aim and, it turns out, the force they’re applying to the ball.

My research finds that there is a relationship between horizontal release angles and horizontal acceleration. In simpler terms, the way the ball is released out of the hand, and therefore where it is aimed, impacts the movement of the pitch.

There are some confounding variables in this specific relationship. The Hawkeye cameras (and, in earlier times, the Pitch F/X technology) report accelerations in three dimensions. These accelerations are measured relative to a fixed point on the field, which happens to be right in front of home plate. Because these accelerations are fixed to one point, the reported values can be biased by the position of release in space. This is far from intuitive, so it might be helpful to consider an example.

Remember that Burnes sweeper from the introduction? It accelerated at roughly 16 feet per second squared in the x-dimension. Imagine that instead of throwing his sweeper from the mound, Burnes threw it from the third base dugout. It’s the exact same pitch as before — same velocity, same horizontal break — but the release point has completely changed. On a fixed global coordinate system of movement measurement, the acceleration in the x-dimension no longer describes the pitch’s relevant movement; all that sideways movement would instead be measured in the y-dimension.

This is an extreme example to illustrate the point, but on a smaller scale, this fixed point measurement system biases acceleration measurements. In order to fix this bias, accelerations can be recalculated to be relative to the pitch’s original trajectory, removing the influence of the release point on the acceleration value. These calculations come courtesy of Alan Nathan; Josh Hejka rewrote them as Python code, making my job easy.

A slight nuance:

The accelerations given by MLB (ax, ay, az) are biased by pitch location.

To make these values location-agnostic, we need to adjust the acceleration vector to be relative to the initial trajectory (i.e. the initial velocity vector vx0, vy0, vz0).

?: https://t.co/CVVNKtG3YM

— Josh Hejka (@hedgertronic) November 14, 2024

Even after accounting for these confounding variables, the relationship between release angles and movement is still present. As the plot shows, it isn’t a particularly strong relationship — when modeled, a two-degree change in horizontal release angle is associated with roughly a foot per second increase in transverse acceleration. But while the relationship is not as strong as that between four-seam fastballs and vertical release angle, it is nonetheless meaningful.

Alternatively, the relationship can be measured using good old-fashioned “pfx_x,” or horizontal movement, which is also measured relative to the pitch’s original trajectory. Why go through all this effort to transform the accelerations? For one thing, I had a good time. And also, isn’t it fun to imagine Burnes throwing sweepers from the dugout?

The plot of horizontal location and horizontal movement, with each pitch colored by its horizontal release angle, illuminates the ostensible lack of a relationship between pitch location — measured by “plate_x” on the plot below — and movement. Draw your attention to the patch of dark blue dots around the -2 line of the x-axis. There are two potential ways for a sweeper to end up two feet off the plate inside. It can be thrown with a horizontal release angle around zero and little sideways movement, or it can be thrown with a negative horizontal release angle and lots of sideways movement.

The same relationship holds true for horizontal release angles and two-seam fastballs after the aforementioned adjustments.

On the individual pitcher level, the relationship is slightly weaker; on average, the r-squared is roughly 0.04 for sweepers, with variation between pitchers on the strength of this relationship. Zack Wheeler’s sweeper movement, for example, appears to be particularly sensitive to release angles:

***

Ultimately, analysts attempt to separate “stuff,” defined as the inherent quality of a pitch, from “location,” defined as where the pitch ends up. But what this research suggests is that, to some degree, these two qualities are inseparable. (I wrote about this a bit on my Pitch Plots Substack last September.) Certain pitches generate their movement profiles because of where they’re aimed out of the hand.

These findings naturally lead to deeper questions about the interaction between biomechanics and pitch movement. While there are variables (arm angle, release height, etc.) that are commonly understood to influence movement, these findings suggest that there are even more granular factors to explore.

Is the angle of the elbow flexion at maximum external rotation the most influential variable? Is it hip-shoulder separation? Torso anterior tilt? Pelvis rotation at foot plant? How much do each of these components contribute to pitch shapes?

Thanks to data from Driveline’s OpenBiomechanics Project, it’s easy to model the relationship between dozens of biomechanical variables and the velocity of the pitch. There are about 400 pitches in the database; by attaching markers to a pitcher moving through space, points of interest can be calculated and then compared to the pitch’s velocity.

In this public dataset, Driveline does not provide the movement characteristics of the pitch. But if the force applied to the ball based on the direction of its aim affects the movement of the pitch, it follows that these variables could be measured in a detailed manner. On the team side, KinaTrax outputs provide the markerless version of these data, providing a sample of hundreds of thousands of pitches from a major league population. Imagine the possibilities.

Correction: A previous version of this article misstated the units of acceleration of Burnes’ backup sweeper. It is feet per second squared, not feet per second.

In his prime — and it was not a long prime — nobody hit a majestic home run like Joey Gallo. It was something about the violence of the swing, the loopy lefty uppercut, the two-handed follow-through, and the way he’d stand up straight right after contact, a confirmation that the baseball was indeed crushed.

Those high arcing blasts powered one of the more bizarre careers of his generation. In the heart of the Three True Outcomes era, he was its emperor, threatening to lead the league in either walk rate, strikeout rate, or home runs in any given year.

Sadly, time passes. Those with prominent residences on Gallo Island now fear foreclosure proceedings. The big slugger has fallen on hard times; last week, he signed a minor league contract with the Chicago White Sox. A non-guaranteed deal with the team that just set the major league record for losses carries some pretty clear subtext. Gallo is hanging off the cliffside of his career, one finger latched to a jagged rock.

It all feels too soon. He’s just 31 years old, a normal and cool age that is in no way old. As Tom Tango’s research shows, bat speed generally starts to decline right at this point, not years before. But even at his best, Gallo lived at the extremes. In his magical 2019 half-season, which unfortunately was cut short by a broken hamate bone, he posted a .635 xwOBA on contact. Across 2,865 player seasons in the Statcast era, only 2017 Aaron Judge topped that figure.

At his apex, nobody — save for one of the greatest hitters of all-time — crushed the baseball like Joey Gallo. He paired that supreme power with some of the lowest chase rates in the league, giving him enough on-base juice to offset the batting averages that made boomers want to gauge out their eyes. That excellent plate discipline allowed him to hunt mistakes in the middle of the plate, mostly fastballs and hanging sliders. His swing was geared for these middle-middle meatballs, and his 70-grade batting eye allowed him to lay off most pitches on the black. Yes, when he got into a two-strike count and was compelled to swing, he most likely was going to come up empty. But he forced pitchers to battle.

Over the last handful of years, though, the other extreme in Gallo’s game eclipsed his prodigious power. Remember those 2,865 player seasons? Two of Gallo’s seasons rank first and second across the decade in the percentage of all swings resulting in whiffs. That decade-leading 44.3% whiff rate came in the 2023 season, when he still managed, I must note, to run an above-average wRC+.

In retrospect, it all started to go downhill after that infamous July 2021 trade to the Yankees. Gallo was coming off perhaps his finest month as a big leaguer, striking out “just” 25.3% of the time, walking nearly as frequently as he struck out, and mashing 10 homers. Painfully, he hit just .160 following the trade, and despite his 16.2% walk rate and usual home run pace, his anemic batting average turned him into a villain with the Yankees. After another dismal half-season, the Yankees shipped him off to the Dodgers; things didn’t get much better in Los Angeles, where he ran strikeout rates that dipped into the 40s for the first time.

Gallo hit free agency for the first time after that 2022 season, and since then teams have made increasingly small bets on his ability to return to his prime form. It started with the Twins in 2023, who paid him $11 million for a single year’s services. Next up were the Nationals, who handed out a $5 million deal, and he turned in his worst season yet. So now here we are, with Gallo at the bleakest end of the baseball universe.

It isn’t hard to see how things ended up like this. Gallo is a big guy who swings hard, and the bills have come due for his high-impact style of play. Over the last two seasons, he battled a sprained shoulder, a strained oblique, a foot contusion, and two separate hamstring strains, the second of which forced him out of action for nearly two months. He even came down with a case of pink eye. His body appears to be breaking down rapidly, and you can almost see the effects of this as he sets up in the box, constantly shifting and readjusting like he’s in the middle seat on a Spirit flight.

Perhaps as a result of all this discomfort, Gallo’s carrying tool is showing signs of erosion. In the second half of 2023, his average bat speed of 73.9 mph ranked in the 84th percentile of hitters. That 2023 mark is the first bat speed data available to the public, and one can imagine that at his peak, Gallo could swing a few miles per hour harder than that, ranking among the likes of Giancarlo Stanton and Kyle Schwarber as one of the fastest swingers in the league.

Gallo’s bat slowed even further in 2024. His average bat speed dipped 1.5 mph, dropping him into the fat part of the bell curve, only a tick above the major league average of 71.3 mph. His once-excellent plate discipline now looks more like passiveness. White Sox manager Will Venable says Gallo will primarily play first base. He is definitively an aging slugger, and his career depends on whether he can revive his famous power skills.

It’s possible that some of Gallo’s bat speed decrease was intentional; in 2023, only Trey Cabbage squared up fewer balls, and that mark improved slightly in 2024. But it’s Joey Gallo. If you have him on your team, you don’t want him trading off power for contact because he’s never going to make enough contact for that to matter. You want him swinging out of his shoes, walloping tanks into the stratosphere.

As my editor Matt Martell pointed out, the White Sox have an institutional history of old slugger resuscitation attempts. There were the ill-fated midseason acquisitions of Manny Ramirez and Ken Griffey Jr., a deal for post-peak Andruw Jones, even the four-year deal they handed out to Gallo’s evolutionary predecessor, Adam Dunn. All these guys landed on the South Side hoping to recapture the magic one last time.

Unlike those other players, though, there are no guarantees that Gallo makes the team, especially because Miguel Vargas is out of minor league options. But let’s just dream for a minute that Gallo took up yoga or any of the other offseason workout routines that prompt players to boast that they’re in the best shape of their lives. Picture this: a .190 average, a 35% strikeout rate, 30 home runs, a permanent spot in the middle of the order against right-handed pitchers. Gallo is one of the strangest and most spectacular players I’ve ever seen. I’m crossing my fingers he gets one last go.

Let’s get this out of the way at the start: The Mariners are pretty good. Their starting pitching is incredible, and some projections systems even think they have a top-10 offense. This is not a Pirates situation, where a core led by Paul Skenes on a league-minimum contract is somehow projected to finish well under .500. In Seattle, the pieces are almost all there. Sadly for fans, “almost all there” might well define this era of Mariners baseball.

The latest expression of Seattle’s complacency came last week, when the team brought back Jorge Polanco on a one year, $7.75 million contract. (The deal is pending a physical.) According to a report from Adam Jude at the Seattle Times, Polanco’s signing means the “Mariners’ roster is effectively set.” For those counting at home, $3.5 million for 37-year-old Donovan Solano, a trade for Austin Shenton, and the Polanco deal represent the entirety of Seattle’s offseason roster upgrades. The Mariners missed the playoffs by one game in 2023 and 2024; they missed it by two games in 2021. They are always good but never great. And the team — or at least ownership — appears totally fine with that. Read the rest of this entry »

You might not know the name Jack Kochanowicz. It’s a tricky name to pronounce, after all. (Ko-hawn-o-witz). He also made his major league debut on the very day in July when the Angels’ playoff odds hit 0.0%. So if this is your first Jack Kochanowicz experience, just know that he’s capable of doing stuff like this:

Another thing you should know: No pitcher last season missed fewer bats. Out of 351 pitchers with at least 50 innings pitched in the 2024 season, Kochanowicz’s 9.4% strikeout rate ranked 351st.

I’ve been fascinated by Kochanowicz because of this contradiction. He can ramp his heater up to 99 mph, and yet his K/9 started with a three. What gives? Read the rest of this entry »