The Blue Jays were posting live batted ball data during batting practice, and this is indeed cool. At the absolute worst, this is an interesting bit of information for anyone who happens to be hanging around. We all have varying appetites for data while consuming sports, but I don’t know anyone who sees a hitter put a ball in the seats and doesn’t immediately think, “I wonder exactly how far he hit that.” Read the rest of this entry »
Triston Casas is making some changes with his left-handed stroke, and he’s doing so with the Green Monster in mind. The Boston Red Sox slugger has historically used the entire field — his pull-center-oppo numbers last season were 38.5%, 38.5%, and 23.0%, respectively — but he wants to take even better advantage of his home park. Bashing with arms bent will be part of that process… at least for now. Compared to his many of his contemporaries, Casas can be a bit of chameleon when it comes to fine-tuning his swing.
David Laurila: You’re making some adjustments at the plate. What are they?
Triston Casas: “It’s more an approach of keeping my swing inside my frame. I want to have the angles of my body — my hips and my shoulders — in alignment, and try to make sure that I’m making contact inside my body. I want to feel like I’m hitting with my arms bent at a certain point.
“As a hitter, you need that triple extension. Your wrists, your front leg, and your back hip are all perfect, at the right time, as you’re making contact. That’s where you get the power.”
Catcher is a thankless job. If you do it successfully, perfectly even, that means that you’re letting highly paid professionals whip projectiles at you as hard as they can hundreds of times a day. Sometimes, other highly paid professionals will divert these projectiles toward you at the last second, or inadvertently hit you with the giant wooden sticks they’re carrying. You have to dive around and flail your limbs, because the only thing worse than getting hit by one of these balls is not getting hit by them; letting them fly by hurts your team. People try to steal from you constantly, so while you’re trying to catch a rock-hard 100-mph pellet, you also have to scan your peripherals. And if all of that isn’t bad enough, here’s the worst part: Sometimes your manager chooses to start Martín Maldonado ahead of you.
I kid, of course, but I’m writing about Yainer Diaz today, and his gradual phase-in to the major leagues is a key part of his major league career so far. Diaz burst onto the big league scene in 2023 with the kind of approach that makes hitting instructors wince, then shrug their shoulders and nod. He swung early and often, took big hacks, and generally acted like he was allergic to taking walks or hitting singles. It worked. He clobbered 23 homers in only 377 plate appearances, spraying loud contact to all fields. He played better-than-expected defense, too, belying his early scouting reports.
Despite that excellent rookie season, Diaz couldn’t displace an aging Maldonado as the team’s primary catcher; he took some reps at DH, but lost those as well when the team got healthy. By the playoffs, he was an afterthought, a pure backup catcher. But when Maldonado (and manager Dusty Baker) departed in the offseason, Diaz ascended to a starting job. Then he struggled – through the All-Star break, he was hitting a so-so .284/.308/.409 with iffy defense. If you’re more of a WAR person, that’s 1.1 WAR, not great. Here’s one story you could tell about Yainer Diaz: a prospect who struggled to break through with regular playing time. Read the rest of this entry »
Back in the days before Junior Caminero — even in the days before Wander Franco — there was Brandon Lowe, a 5-foot-10 second baseman who anchored the Tampa Bay Rays’ lineup during its most fecund period. As the Rays made the playoffs five years in a row from 2019 to 2023, and won the pennant in 2020, Lowe was at the center of it. He posted a 151 wRC+ in 2020, and a year later he hit 39 home runs.
That’s tied for the second-most homers in a season in Rays history, up among a bunch of guys (Carlos Pena, Logan Morrison, Jose Canseco) who are so big they could fit Lowe in their jacket pocket.
Now, as Caminero is bashing his way into the everyday lineup, Lowe is at an inflection point in his career. He’s struggled to stay healthy the past three years, and he turns 31 in July. And because everything the Rays touch has to be viewed through this lens: Lowe is in the final guaranteed season of his seven-year contract. His 2026 club option is quite affordable, even for Tampa Bay ($11.5 million), but there’s only one option year. Read the rest of this entry »
You have to hand it to the Mets. There really does seem to be something ineffable that brings drama to Queens. No, I don’t mean the LOLMets meme, the belief that things will find a way to break every year, because I don’t really think it’s true. The Mets aren’t cursed. But they do have a way of making things interesting. It’s never all smooth sailing, but they’re never completely down and out either. There’s always a little more to explore at Citi Field, and this offseason is no exception. The Mets are on top of the world, because they signed Juan Soto, one of the biggest free agent prizes of all time. And they have their backs to the wall, because two pitchers they signed to assemble a playoff rotation are already injured.
Frankie Montas was the first casualty. He felt discomfort after his very first bullpen session of spring training, and a lat sprain means that he won’t be able to throw for another 5-7 weeks. Given that the regular season is five weeks away, and that Montas had done essentially no buildup before his injury, we’re talking about multiple months of absence.
The good news is the Mets built their rotation this offseason to withstand injuries. After all, Montas wasn’t the most prominent starting pitcher they signed this winter. Sean Manaea holds that distinction; he was the best pitcher on last year’s team, and though he hit free agency, he signed a three-year deal worth $75 million to come back. That’s not quite ace money in today’s game, which is perfect: Manaea’s not quite an ace, just a solid playoff starter with upside. Except, he’s also hurt now. After feeling some discomfort of his own, an MRI revealed a right oblique strain. Read the rest of this entry »
In a generally bleak 2024 season for the Toronto Blue Jays, one of the few bright spots in that Kafkaesque wasteland was the return of Vladimir Guerrero Jr. as a force to be reckoned with in the lineup. Guerrero followed up his MVP-caliber performance in 2021 with a solid-but-underwhelming 2022 season and a below-average 2023, and there were real questions about his value as a player as he neared his expected free agency after the 2025 campaign. His .323/.396/.544, 165 wRC+, 5.5 WAR line last year was a dramatic demonstration that his 2021 season was a lot more than a stone-cold fluke. Free agency beckons, and the Blue Jays are down to the last year of his services before he reaches the open market. Guerrero set the deadline to work out an extension with Toronto for February 17, and that date has come and gone without an agreement.
The great Irish writer Seamus Heaney often spoke of the good that poetry could do, both for individuals and the world at large. To that point, he once lamented in jest that “poetry can’t be administered like an injection.” Admittedly, I stumbled upon that quotation by accident, deep within an internet rabbit hole I tumbled down while researching the American baseball pitcher Andrew Heaney. (Sometimes I forget to search for more than just a last name.) Nevertheless, I was so taken with Seamus Heaney’s message that I felt inspired to inject his words into my writing and analysis today.
Between my finger and my thumb
The squat pen rests.
I’ll dig with it.
-From “Digging” (1966)
On Thursday, the Pirates and Heaney – Andrew, to be clear – agreed to a one-year, $5.25 million contract for 2025. After two years with the Rangers, the veteran left-hander will slot into Pittsburgh’s rotation for his age-34 season.
A first-round pick by the Marlins in 2012, Heaney spent three seasons in their organization. He climbed to the summit of Miami’s top prospect list in 2013 and made his big league debut the subsequent summer. Following the 2014 season, he was the headlining prospect in a fascinating trade with the Dodgers that brought Dan Haren, Dee Strange-Gordon, and Miguel Rojas to the Marlins in exchange for Heaney, as well as future Dodgers stalwarts Enrique Hernández and Austin Barnes, and catcher-to-pitcher convert Chris Hatcher. Hours later, the Dodgers flipped Heaney to the Angels for Howie Kendrick. At the time, Kendrick was coming off a 4.6-WAR season for the reigning AL West champions, just to offer some sense of how highly the Angels must have valued Heaney. Read the rest of this entry »
Xavier Isaac’s game is built around damage. No. 98 on our recently-released Top 100, the 21-year-old, left-handed-hitting Tampa Bay Rays prospect has, according to our lead prospect analyst Eric Longenhagen, “some of the most exciting power in pro baseball.” Getting to it consistently will be his biggest challenge going forward. As Longenhagen also wrote in his report, “By the end of the season, [Isaac] had a sub-60% contact rate, which is not viable at the big league level… [but] if “he can get back to being a nearly 70% contact hitter, he’s going to be a monster.”
While Isaac’s 143 wRC+ between High-A Bowling Green and Double-A Montgomery was impressive, his 33.3% strikeout rate was another story. The built-to-bash first baseman knows that cutting down on his Ks will go a long way toward his living up to his lofty potential. At the same time, he’s wary of straying too far from his strengths.
“I’ve tuned up my power, and now I need to get my contact up a little bit more,” Isaac told me during the Arizona Fall League season. “It’s like a tradeoff, kind of. I’m going to strike out, but I’m also going to hit the ball a little harder. I have a lot of power, so some of it is about going up there and taking a risk. I obviously don’t want to strike out — I‘m trying to put it in play — but I also don’t want to be making soft contact.”
That’s seldom a problem when he squares up a baseball. Not only does his bat produce high exit velocities, he knows what it feels like to propel a pitch 450-plus feet. He doesn’t shy way from the power-hitter label. Asked if that’s what he is, his response was, “For sure.”
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.
Credit: Filipa Ioannou
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).
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.
Editor’s Note: An updated version of the Top 100, which incorporates Eric’s spring looks through the end of March, is available to read here. As always, full scouting reports and tool grades for every ranked prospect can be found on The Board.
Below is my list of the top 100 prospects in baseball. The scouting summaries were compiled with information provided by available data and my own observations. The ETAs listed generally correspond to the year a player has to be added to the 40-man roster to avoid being made eligible for the Rule 5 draft. Manual adjustments are made where they seem appropriate, but I use that as a rule of thumb.
All of the prospects below also appear on The Board, a resource the site offers featuring sortable scouting information for every organization. It has more details than this article and integrates every team’s list so readers can compare prospects across farm systems. It can be found here.
And now, a few important things to keep in mind as you’re perusing the Top 100. You’ll note that prospects are ranked by number but also lie within tiers demarcated by their Future Value grades. The FV grade is more important than the ordinal ranking. For example, the gap between Sebastian Walcott (no. 4) and Quinn Mathews (no. 32) is 28 spots, and there’s a substantial difference in talent between them. The gap between Chase Petty (no. 42) and Cam Smith (no. 70), meanwhile, is also 28 numerical places, but the difference in talent is relatively small. Read the rest of this entry »
