In his later years, sportswriter Red Smith was prone to waxing philosophical about the distance between bases in baseball. The language he used varied, as did the way it was transcribed and repeated, but in the most streamlined form of his aphorism, Smith asserted that the 90 feet between bases is as close as humans can come to perfection. Smith was neither nearly the first nor nearly the last to marvel at what Roger Kahn called the “magic 90 feet apart.” Before the observation became associated with him, Smith himself attributed similar sentiments to Branch Rickey and Moe Berg.
Decades after Smith’s odes to the diamond’s dimensions, and more than 160 years after the distance was standardized, 90 feet between bases still works well enough. (Although the actual distance, accounting for the sizes and orientations of the bags and home plate, is technically neither 90 feet nor uniform between bases.) Runners are bigger and faster, but fielders are faster and stronger, and the balance between them is mostly maintained. Well-placed slow rollers still turn into infield hits, routine choppers sent directly at defenders still yield easy outs, and numerous force and steal attempts still produce plays too close to call with confidence. That a rule laid down a few years before the first shell was fired at Fort Sumter remains suitable today cements the perception that, as, Kahn wrote, “the ball field itself is a mystic creation, the Stonehenge of America.” To tamper with its layout would be sports sacrilege.
But the ball field, like Stonehenge, didn’t spring forth fully formed. Through trial and error and hard labor, the builders of baseball established how long the basepaths should be, just as ancient Britons transported and raised heavy slabs of stone. In both cases, the architects built and improved on their predecessors’ more modest foundations. (Some suspect that the basepaths were once 75 feet, and the structures at Stonehenge were once rotting timber.) And while 90 feet between bases may still seem close to perfection, the second-most-famous measurement on the field—the 60 feet, 6 inches between the pitching rubber and home plate—arguably hasn’t held up as well.
In an era of giant pitchers, rising pitch speeds, and spiking strikeout rates, baseball’s best hope of bringing back balls in play may well lie in moving the mound—not downward, but back, to a point perhaps a foot or three farther from the plate. MLB’s official historian, John Thorn, isn’t endorsing the idea, but he’s “open to changes that some might see as radical” to combat the contact decline. “Baseball has periodically stepped in, since the 1870s, to correct course on trends that might deter spectators,” Thorn says. “It is hardly heresy to say that it may do so again.”
Last week, MLB stepped in to announce a slew of experimental rules that will be tested at various levels of the minor leagues in 2021. The new rules—most of which were previously implemented at MLB’s behest in the independent Atlantic League in 2019—were “designed to increase action on the basepaths, create more balls in play, improve the pace and length of games, and reduce player injuries.” They include automated strike zones, timers between pitches, batters, and innings, restrictions on shifting, pickoff moves, and the number of pickoff attempts, and bigger bases (and thus, shorter basepaths—sorry, Red). For a few reasons, they don’t include moving the mound. But some evidence indicates that pushing the pitcher’s starting point back from the place where it’s stood since 1893 would be among the most effective and least obtrusive means of suppressing strikeouts.
Anyway, this is MLB not addressing the real issue — pitchers are too close to batters — and instead trying to win the press conference.— Joe Sheehan (@joe_sheehan) March 12, 2021
Baseball’s problem isn’t where the shortstop is standing. Its problem is that the shortstop has nothing to do 40% of the time. Fix that.
The rationale for moving the mound back is simple: Modern pitchers are much taller and throw far harder than 19th-century pitchers. Thus, their pitches are being released closer to home plate and flying faster toward their targets, which means that today’s hitters have less time to react. Four years ago, 29-year-old Buster Posey—then baseball’s best-hitting catcher—remarked on an influx of flamethrowing pitchers capable of touching triple digits. “I’m about ready to move the mound back a little bit,” he joked. Posey was responding to a significant increase in average pitch speeds even in the fairly short time since his 2009 big league debut. From 2008 to 2020—the period covered by MLB’s PITCHf/x and Statcast pitch-tracking systems—the average speeds of four-seam fastballs, all fastballs combined, all breaking balls combined, and all off-speed pitches combined all rose by roughly 1.5 to 2 miles per hour.
That’s just the latest spurt of speed increases. Pitch data recorded by Baseball Info Solutions video scouts from 2002 to 2007 shows an uptick of another 1-2 mph over that span for most pitch types. And while the public pitch-velo trail goes cold there, information from a Reds scouting database analyzed by The Ringer in 2019 suggests that speeds rose substantially over the preceding decade, too. Those leaked Reds records don’t begin until almost a century after the rubber took up station at 60 feet, 6 inches, which means we can only speculate about the full extent of the speed increase since 1893—a period that encompasses a great growth of athletic talent, fueled by a massive expansion in the pool of potential pitchers, increasingly rigorous approaches to scouting and player development, and an explosion in the financial incentive to pursue playing baseball professionally.
The current pitching distance was set less than a decade after full overhand deliveries were first permitted and hitters lost the right to specify whether they wanted pitches high or low. Pitchers have been throwing from 60 feet, 6 inches since long before integration and internationalization; before the rise of relief pitching and an invasion of one-inning arms; before the advent of weight training and scientific velocity development; before recent advances in injury prevention and treatment; before the invention of velocity-tracking technology and the subsequent quantification of (and fixation on) the value of throwing hard.
And also before the player population experienced a growth spurt. Modern MLB pitchers, weighted by workload, are almost 6-foot-3, on average, more than 4 inches taller than they were in 1893.
Taller pitchers generally have longer limbs, which allow them to stride and extend their arms farther forward. According to Statcast extension data provided by Baseball Prospectus, MLB pitchers from 2017 to 2020 released the ball 6.15 feet in front of the rubber, on average, or less than 54.5 feet from the plate. That data confirms the connection between height and extension, although the correlation (0.3) is somewhat weak, probably because shorter pitchers who make the majors tend to compensate for their statures by punching above their height in terms of extension, Lincecum-style. The momentum-generating mechanics of today’s flexible and ultra-athletic pitchers likely also give them greater extension than 19th-century moundsmen even on an inch-per-inch basis. Doug Thorburn, a pitching analyst formerly of Baseball Prospectus and the National Pitching Association, says that based on his video review of pitching mechanics from earlier eras, “the extremes of long ago in extension would compete with the extremes of today. But my hunch is that the average extension is better in 2021.”
Chris Young, who pitched in the majors from 2004 to 2017, didn’t get great extension (or speed) for his size, but he can testify to the fact that pitchers have gotten a lot larger. Young stands 6-foot-10, or 8 inches taller than any pitcher who threw more than three games in 1893. “With the average velocity having increased significantly over the past decade, I think at some point the dimensions have to be evaluated to see if we are physically exceeding the way the game was designed,” Young says, adding, “Today’s athletes are bigger, faster, stronger, and you have to accommodate that to preserve the entertainment value of the game.”
Granted, position players have gotten more talented too, and air-oriented launch angles have allowed them to lift the lively ball enough to prop up scoring. But sharper eyesight and swifter reactions aren’t enough to help hitters compensate for faster pitch speeds and stop contact from cratering. They haven’t yet benefited from tech-aided training to the extent that their pitcher opponents have, and pitchers are poised to take advantage of new advances in pitch design and biomechanics. The velocity surge has leveled off lately, as has pitcher height. But absent intervention, MLB would be stuck with its powerful-pitcher problem, just as the NHL would with its big-goalie problem and the PGA would with its big-golfer problem. Bigger isn’t always bad: In basketball, where dunks are exciting and the offense and defense have sprouted in synchrony, 10-foot rims have sufficed (with some dissenters) since 1891. But when athletes outgrow their environments in a way that leads to less entertainment, there’s an obvious solution: Make their jobs more difficult, as the NFL did in 2015 when it moved extra-point kicks from the 2-yard line to the 15-yard line in a successful bid to make kicks less automatic and encourage teams to try for two-point conversions.
Young was hired as the Rangers’ general manager in December, but before that, he worked as an executive at MLB, joining the league office as vice president of on-field operations, initiatives, and strategy in May 2018 and rising to senior vice president in charge of on-field operations and umpiring in February 2020. Although Young acknowledges that some fans, players, and media members are loath to tinker with a tradition that dates back almost 130 years—why mess with supposed perfection?—he points out that despite the longstanding continuity in pitching distance, “We’re not playing the same game that has been played historically. I know that there’s a nostalgia attached to 60 feet, 6 inches, but I think that the style of the play is probably more important than the distance between home plate and the pitcher’s mound.”
The league’s style of play has become increasingly contact-averse. Hitters struck out in 23.4 percent of all plate appearances last season, more than four times as often as the 5.2 percent rate in 1893. The K rate has climbed slowly but fairly steadily since the beginning of major league baseball, plateauing or receding only when steps were taken to restrain it. Although the latest upward trend has been especially steep and sustained, the addition of the NL DH in 2020 presented a promising opportunity for at least a temporary pause. However, even pulling impotent pitchers out of the batter’s box couldn’t halt the inexorable ascent, which has stretched to a record 15 consecutive seasons.
There’s every reason to expect the streak to reach 16 years in 2021, especially in light of the reversion to NL pitcher hitting (barring an improbable, buzzer-beating deal to restore it). Pitchers struck out in 43.5 percent of their plate appearances in 2019, and they’ll likely whiff even more often in 2021 after a long layoff.
Increased speed and extension aren’t the only factors inflating whiffs. Moving the mound back, in isolation, would do nothing to address some of the others: an expansion of the strike zone, accelerated by a tech-aided adherence to the rulebook zone and a data-driven cultivation of catcher framing; an analytics-fueled reduction of the stigma surrounding offensive strikeouts, enabled by the epiphanies that strikeouts aren’t any more damaging, on average, than other types of outs, and that they sometimes go hand in hand with patience and power; the low-drag ball that makes it more rewarding for hitters to swing for the fences (as does the shift, albeit only when lefties are up); and teams’ efforts to prevent hitters from facing the same pitcher three or four times in a game.
But blunting the velocity advantage would be a big step, and moving the rubber back by, say, 2 feet would have a meaningful effect on pitches’ perceived speeds. When I visited this topic for the first time almost seven years ago—during the 2014 season, when the strikeout rate cracked 20 percent—I asked Alan Nathan, a professor emeritus of physics at the University of Illinois at Urbana-Champaign and a decorated expert on the physics of baseball, to calculate the effect on flight time of moving the mound back. According to Nathan’s equations, a 95 mph pitch released at 57 feet would have the same flight time as a 91.7 mph pitch released at 55 feet.
Thrown from 2 feet farther back than usual, that 95 mph pitch would fly for about 15 more milliseconds before reaching the plate—a roughly 4 percent increase in travel time. But because batters can only observe a pitch for about half of its roughly 400-millisecond total flight time before deciding to swing—after that, it’s too late for the hitter to process and apply any new information—Nathan says the increase in useful observation time is actually about twice the increase in flight time, or approximately 8 percent in this scenario. That doesn’t sound enormous, but it would hand hitters back much of the reaction time that pitchers have whittled away in the 21st century.
It's nowhere near that simple. Teams pay players based on their value, so you're advocating to override the free market - a dangerous idea. The fix is to make the skill of putting the ball in play *more valuable*. Move the mound back. Deaden the ball. The market will fix itself. https://t.co/jB5dZsVC6Q— Rany Jazayerli (@jazayerli) January 14, 2021
Not everyone agrees that moving the mound back and dialing down perceived velocity would reduce strikeout rates. Although the ongoing strikeout-increase streak predates the days of data-driven pitch design, optimized pitch selection, and soaring spin rates and breaking-ball movement, Kyle Boddy, founder of player development facility Driveline Baseball and director of pitching for the Reds, believes that much of the recent strikeout spree stems from hitters seeing a steady barrage of nasty non-fastballs—which would move even more from farther back. Consequently, he thinks the change would hurt hitters. “Everyone focuses on reaction time, but hitters also expect certain shapes on pitches, and increased distance gives the pitch more time to break,” Boddy says. “I strongly, strongly suspect increasing the distance will lead to increased walks, increased strikeouts, and fewer homers.”
Further suppressing balls in play and intensifying the three true outcomes—which accounted for a record 36.1 percent of plate appearances last season—is the opposite of the intended effect. But Boddy’s opinion seems to put him in the minority, both about the breaking-ball calculus and about the overall impact on the pitcher-batter balance of power. Nathan doesn’t agree that the added breaking ball movement would help pitchers. “The amount of movement on a pitch depends on the square of the distance over which the pitch travels,” he explains. “For example, moving the rubber back 1 foot would increase the distance by about 2 percent, which increases the movement by about 4 percent. That is probably the origin of the statement that it helps pitchers. On the other hand, the batter has more time over which to observe the pitch … 2 percent more time, in my example. So my own guess is that this particular effect is a net wash, favoring neither batter nor pitcher.”
A front-office analyst who asked not to be named comes down on the side of increased offense. “I think added reaction time will help hitters more than pitchers,” the analyst says. “I think pitchers would really struggle to throw bigger breaking balls for strikes depending on the distance.” The analyst adds that prior proprietary research suggests that subtracting 2 feet of pitcher extension, all else being equal, is probably worth about .003 runs per pitch in favor of the batter. In this case, all else wouldn’t be equal—pitch movement would be slightly augmented—so the benefit to the batter might be more like .002 runs per pitch, which would boost scoring by about .25 or .30 runs per team per game. (The analyst adds that the three true outcomes could still increase if hitters adopted more uppercut-oriented swings to launch pitches on more negative approach angles.)
Glenn Fleisig, the research director at the American Sports Medicine Institute and a consultant to MLB, also suspects that moving the mound back would help hitters. “The extra break is going to be an extra challenge,” he concedes, “but I think the extra time would be beneficial.” And Young believes that moving the mound back is the best way to address the strikeout’s ascendance.
All of these parties are experts on pitching, physics, or both. Not all of them agree. So how do we decide what the true effect would be? “The only way to know for sure is to test it,” Boddy says.
About that: In effect, a few field tests have already been performed. The pitching distance was lengthened substantially three times in the late 19th century, as the fledgling National League refined its rules and periodically sought to pump up offense deflated by other developments. In 1881, the minimum pitching distance was pushed from 45 feet—where it had stayed since a convention of New York clubs codified many of the game’s foundational laws in 1857—to 50 feet, in an attempt to “increase the batting.” As of 1887, the pitcher was required to keep his back foot on the border of the “pitcher’s box” 55.5 feet from home when delivering the ball. And in 1893, the box was replaced by a slab positioned another 5 feet farther back: 60 feet, 6 inches. (A persistent story about that pesky 6 inches resulting from a surveyor’s mistake is a myth.) It’s impossible to isolate the effects of the changes in distance, because baseball was more malleable in those days, multiple rules were often in flux, and the data is full of confounding factors. However, each season that featured a major move back coincided with the strikeout rate sinking and offense rebounding significantly, especially after full overhand pitching was approved in 1884.
Previous MLB Pitching Distance Changes
In the 19th century, nobody had ever seen a slider, let alone a splitter, and the stuff we take for granted from a fifth starter today would have reduced contemporary commentators to the equivalents of Ewoks worshipping C-3PO. But it’s still suggestive that in both cases, strikeouts and offense shifted in the intended directions. And the motivations for pushing pitchers back were strikingly similar to those on the minds of many fans today.
In November 1892, just before the final 5-foot move, Sporting Life editor Francis Richter endorsed a multipronged plan by Philadelphia Record sportswriter W.R. Lester “to restore the game of base ball to high favor.” (Even before it was spelled with one word, baseball was said to be dying.) Lester and Richter believed that this blueprint, which called for the pitching distance to be placed in the center of a slightly enlarged diamond, would bring about “the restoration of the proper equilibrium of between the two great principles of the game—attack and defense.” Richter’s description of the desired results is too pertinent not to excerpt.
With the pitcher reduced to the ranks, nine men instead of two will play the game; there will be a marked increase in that feature so dear to the popular heart—clean, hard batting; less pitchers’ intimidation of the batsman and fewer chances of injury to the batter; more baserunning, because of the greater number of men to reach bases; more brilliant fielding, because of the increased number of chances for the infielders and outfielders; better fielding chances and less danger for the pitchers; more swing, dash and go to delight the spectators, for whom the magnates should legislate.
All of that sounds as appealing in 2021 as it did in 1892. Who wouldn’t want to swing, dash, and go?
Less than four months after Richter signal-boosted Lester—and future Hall of Famer Henry Chadwick chimed in to call Lester’s suggestions “most practical”—the NL adopted the 60.5-foot distance in a 9-3 vote. As the table above indicated, equilibrium was restored. A.J. Flanner of the St. Louis Post-Dispatch wrote in November 1894, “The monotonous strike out game has been legislated into a reminiscence, and in its stead is a system of play which requires nine experts to carry it to a full measure of success. Increased batting has given rise to more opportunities for brilliant fielding, involving perfect handling and throwing of the ball.” Aside from the “outrageous conduct of the players, which became so offensive in some cases … that riots resulted,” it all sounds swell.
We don’t have to turn back the clock quite so far to find precedents in baseball’s closest cousin, softball. The pitching distances in both men’s and women’s softball gradually migrated farther from home throughout the 20th century, beginning at 30 feet and eventually landing at 46 feet for men and 43 feet for women. The NCAA made the move from 40 feet to 43 feet in women’s fast-pitch softball in 1987, following a period of offensive stagnation. (The NCAA says the change became official in 1988, though contemporary accounts make it clear that it happened the preceding season.)
“For many years there was a regular drumbeat that softball had become a boring game because of the dominance of pitching,” recalls National Fastpitch Coaches Association Hall of Famer Mary Higgins, who coached Creighton from 1977 to 1993 and served on the coaches committee that approved the change. The increased distance, she says, “made the game more offensively-minded and thus, more engaging for fans.” The NCAA’s stats support her recollection, although more measures followed to keep the Ks in check. The National Federation of State High School Associations followed the NCAA’s lead in 2009, and the 3 added feet made the game less static at the lower level too.
NCAA Division I Softball Stats, 1982 to 1988
Last month, at The Ringer’s request, a team at Driveline Baseball conducted one additional demonstration. On February 17, a group of nine collegiate hitters faced a total of 426 pitches—a mix of 90 mph fastballs and 75 mph curves, with constant spin rates and directions, delivered by an iPitch pitching machine—from 57 feet, rather than their normal 55. The Driveline staff tracked their swings and batted balls with Blast Motion, TrackMan, and HitTrax sensors.
A pitching machine in an indoor cage is much more predictable and a lot less intimidating than a living pitcher in a game situation, but the consistent conditions provided a controlled experiment, albeit one with a fairly small sample. Compared to their 55-foot baselines, the hitters collectively raised their swing rates by 3.1 percentage points, their contact rates by 4.8 percentage points, their pull rates by 6.0 percentage points, and their hard-hit rates by 16.8 percentage points when they had 2 extra feet to time their targets. There’s nothing stopping MLB from organizing a larger-scale study along the same lines or paying amateur or ex-pro players to be willing subjects in experimental-mound scrimmages.
In 19th-century National League baseball, 20th-century softball, and 21st-century high-tech training, increasing the pitching distance produced corresponding increases in contact and offense. None of those scenarios is precisely analogous to modern major league games, but to borrow a phrase from Red Smith, it’s the closest we can come to perfection—so far.
As late as mid-March of 2019, the Atlantic League and MLB were agreed on moving the mound from 60.5 feet to 62.5 feet in the second half of the Atlantic League season. Although a 6-inch or 1-foot move may have been an easier sell, a 2-foot difference would help clarify the effects, with the first half providing a basis for comparison. But in early April, the two leagues tabled the mound-distance move, tentatively until the second half of the following season. Of course, the coronavirus pandemic ended the 2020 Atlantic League campaign, and the dream of moving the mound, before that part of the plan for the season was formalized.
According to a source familiar with the talks between leagues, the 2019 plan was scuttled largely over worker’s comp concerns. Pitchers were (and are) wary of throwing from a different distance than the one they’ve always known, and any pitcher who gets injured while working from 2 feet farther back may blame the mound, even if a link can’t clearly be established. But multiple sources with knowledge of the league’s thinking confirm that support for exploring the mound distance change has grown at the commissioner’s office over the past few years, and there’s still a possibility that the mound move will be put into action during the 2021 Atlantic League season, which opens on May 27. From a diplomacy standpoint, testing a new mound distance in affiliated ball may be a nonstarter, and a successful trial in one of MLB’s newly christened “Partner Leagues” could help get the union on board. Depending on the details of the next CBA, commissioner Rob Manfred might have the power to impose a new mound distance without the players’ approval (as he did with the three-batter minimum rule), but doing so might prompt a pitcher revolt.
It’s understandable that pitchers would be uneasy about the mound moving under them, and no athlete with a limited time in their prime is eager to be treated as a guinea pig. To assess the real risks, MLB approached Fleisig and ASMI in February 2017 about studying the effects of lowering the mound, and again in January 2019 about studying the effects of moving the mound back. The resulting MLB-sponsored studies, published in January 2019 and February 2020, respectively, reached a couple of counterintuitive conclusions. Fleisig and his colleagues found that lowering the mound might “slightly reduce shoulder and elbow kinetics, possibly reducing the risk of injury.” But no significant differences in ball movement were detected at the lower elevations.
“Dropping the mound, to me, is not as radical an idea, but our study showed it might not give the advantages you’d think it would,” Fleisig says. Although it’s commonly believed that lowering the mound from 15 inches to its current 10-inch height played a part in reviving offense after the anemic 1968 season, the more robust offensive environment of 1969 may have had more to do with the strike zone returning to its smaller 1961 size.
In the second study, the ASMI team monitored the biomechanics and ball behavior of pitchers as they threw from the standard distance, 2 feet farther back, and close to the geometric center of the diamond (63 feet, 7.5 inches). As expected, the longer distances yielded longer flight times and increased pitch movement. But the pitchers’ kinematics didn’t differ significantly at the longer distances, leading the researchers to conclude, “It is unlikely that moving the mound backwards would significantly affect pitching biomechanics and injury risk.”
Although the paper didn’t estimate the offensive ramifications, “The most important thing from my perspective is that it showed it would not change the risk of injury to the players,” Fleisig says. “I think that’s the first step before Major League Baseball can consider these things, and it has passed that test.” If Fleisig is right, then moving the mound back might actually help keep players healthy. As Lester and Richter noted in 1892—when thrown and batted balls moved much more slowly than they do today—pitchers would have more time to protect themselves from comebackers, and batters (who’ve been pummeled by pitches at historic rates in recent years) wouldn’t be hit as hard. (Pitchers might also be better at checking runners and racing to first, though a few more dribblers would become base hits.)
In theory, pitchers shouldn’t have to dramatically alter their approaches on the mound from 2 feet farther away. Fleisig and Nathan note that the necessary changes in the angles of release at 60.5 and 62.5 feet are negligible, and pitchers already raise and lower their sights depending on whether they want to aim upstairs or bury a ball in the dirt. Young observes that a max-effort throw at 95 mph from the current pitching distance would easily sail to the backstop if the catcher weren’t in the way. So from 62.5 feet, the pitcher wouldn’t have to throw harder than usual; the ball would simply be stopped slightly farther away. (As it is, the distance at which the catcher crouches varies by a foot or two from catcher to catcher and pitch to pitch.)
That said, structural hurdles remain, in addition to the difficulty of convincing players and fans to go against the grain. For one thing, while leagues with lower velocities wouldn’t need distance adjustments, many, many mounds and rubbers across the country would have to be moved to keep conditions consistent throughout MLB’s developmental pipeline. That may be more manageable than banning foreign substances, but who would handle the grunt work and foot the bill? For another, the change in the mound would probably have to be paired with a more aggressive deadening of the baseball (or a strike-zone reshaping) to stop hitters from launching more and more homers, and to prevent excess scoring and longer games.
But if the mound movement were to work as designed, it could help replenish baseball’s ebbing biodiversity. The readjusted sport might be slightly more hospitable to slap hitters and, perhaps, older hitters who’ve struggled to stay relevant in an era that favors youth. Moving the mound back might also offer pitchers blessed with less speed a helping hand. “It’s really important that our game does not become one-dimensional, focused on power—both power offensively and power defensively with power pitching,” Young says. “And I think that right now velocity seems to be the no. 1 predictor of success as a pitcher.”
Sixty feet, 6 inches isn’t a round number; it’s almost asking to be altered. Moving the mound back a bit would barely be noticeable from afar. We’re all accustomed to the idea of mounds moving farther back as young athletes grow; why not move them as major leaguers grow? And after last year’s pandemic-shortened season showed that games can last seven innings, extras can start with a runner on second (another idea baseball borrowed from softball), and the playoffs can contain the majority of teams, then why can’t the rubber be 2 feet farther away? Because baseball grumps would grumble? In baseball, change is a tradition, too.
Hunter S. Thompson once wrote about his own plan to fix baseball, “Purists will bitch and whine, but so what? Purists will Always bitch and whine.” And strikeouts will always increase, unless something stops them.
Thanks to Dan Hirsch and Kenny Jackelen of Baseball-Reference, Lucas Apostoleris of Baseball Prospectus, Tom Shieber of the National Baseball Hall of Fame, and Noah Thurm, Kyle Lindley, Richard Prigatano, Luisa Gauci, and John Soteropulos of Driveline Baseball for research assistance.