Pitchers are always looking to chip away at the platoon advantage. Two of the most common weapons in doing so are the changeup and curveball. The former fades away from opposite-side batters and from the barrel as the bat whips through the zone. Most of a curveball’s movement, meanwhile, is vertical; no matter the handedness of the batter and corresponding bat path, the pitch can duck under the bat as the batter makes contact. Sliders, though, generally have a large platoon split, to the detriment of the pitcher, as they move more horizontally relative to vertically and toward the pitcher’s glove side. This leads the ball towards the barrel of an opposite-handed hitter, giving him more of an opportunity to make contact.

Cutters are interesting in this regard. Given the movement of the pitch, you would expect it to have significant platoon splits like a slider. The ball moves toward a pitcher’s glove side, albeit generally not as far as a slider; an opposite-handed hitter would have a better chance putting the barrel on it. But this is not the case, according to research from Max Marchi done back in 2010, as he found that cutters were in the middle of the pack with respect to pitch-type platoon splits. It still had more favorable splits when the batter had the platoon advantage, but that is the case for all pitches in general.

So why does the cutter not have much of an effect on the platoon advantage despite its break? As MLB.com explains it, the magnitude of the horizontal break is subtle enough to catch a hitter expecting a four-seamer off guard. Thus, when he swings, the movement of the pitch forces the batter to fight it off his hands and either induces weak contact or breaks the bat altogether. My thesis was that players are turning to the cutter because of these neutral platoon splits, as heavily using a pitch that works well to hitters from both sides makes you harder to predict. Read the rest of this entry »

There have been some scary moments in the first few weeks of the 2021 major league season. On April 28, Phillies Manager Joe Girardi was ejected after both Didi Gregorius and Bryce Harper were hit by pitches while they were playing the Cardinals. Harper’s incident was particularly scary as he was hit in the face with a 97 mph fastball. On April 5, Cubs catcher Willson Contreras was plunked by a 93 mph fastball to the helmet. Two days later Reds rookie Jonathan India had a similar moment after a fastball ricocheted off his helmet.

It’s not your imagination: batters are being hit by wayward pitches at a record clip. Ken Rosenthal of The Athletic made note of the trend this morning. Baseball Prospectus’ Rob Mains recently published an excellent breakdown of this year’s record-setting pace for hit batsmen. I was particularly taken aback by this chart showing that prior to 2018, no season in baseball history had a hit batsman in more than 1 in 103 plate appearances:

Mains continues:

There was one batter hit per 96 plate appearances in 2018, a new record. It fell further, to 94, in 2019. Then all the way to 81 in last year’s short, weird season.

This year? Through Tuesday night’s games, it’s down to 74.5. Batters are being hit thirty-eight percent more frequently than in 1901. There are just over eight hit batters for every five just a decade ago. We’re averaging 0.997 hit batters per game in 2021, a single HBP shy of one per game—a level the sport’s never approached. Batters so far have a .309 on-base percentage. Hit batters account for thirteen points of that figure. Ten years ago, there were only eight points of hit batters in MLB’s .321 OBP.

I wanted to take a look at possible reasons the HBP rate is at record levels so far in 2021, but first we need to be clear about which parts of this trend are continuations from previous seasons and which parts are actually new. In 2019, Devan Fink demonstrated that the HBP rate per plate appearance was approaching the highest levels seen since the early 1900s. He looked at increased velocity and reliever usage to demonstrate that while a pitches’ speed didn’t necessarily mean a pitcher had worse command, relievers had a larger share of HBP than their starting counterparts. Read the rest of this entry »

On Wednesday afternoon, Liam Hendriks entered a tough situation. There were two outs in the bottom of the ninth, but his margin for error was nonexistent. The bases were loaded, and the White Sox were locked in a tie game. One hiccup in command, four slightly misplaced pitches, and the game would be over.

Do pitchers have less command when they enter? Is it worth worrying about whether a pitcher might not have it that day? I have no earthly idea, so I decided to investigate. First things first, though: I wasn’t actually sure what I was investigating. Time for some experimental design.

What about the walk rate, but only on the first batter faced by a new reliever? That’s certainly a number I could look up. That checks in at 8.1% from 2015 to present (I used the Statcast era even though there’s no Statcast data involved in this query, just for consistency’s sake). Over the same time frame, the overall reliever walk rate is 9.3%. Case closed, let’s go get brunch.

Only, that’s a bad comparison. We’re not comparing apples to apples. If we’re actually going to look into whether pitchers are particularly likely to come in and not have it, we need to compare like to like. Take the immortal Sugar Ray Marimon, who made 16 appearances for the Braves in 2015. He was a one-hit wonder, though “wonder” might be strong: he compiled a 7.36 ERA in 25.2 innings before decamping to Korea. Read the rest of this entry »

On Monday, I examined the new baseball’s impact on April home run totals. In sum, home runs were down in April 2021 compared to April 2019, with the home run per batted ball rate dropping by roughly 0.45 percentage points, a figure that would result in about an 8% decrease in home runs from ’19 to ’21, under the assumption that hitters receive roughly equal plate appearances in each season. (Due to seven-inning doubleheaders and the new extra inning rules, though, that won’t happen, but it’s still good to compare apples-to-apples to estimate the impact.)

After sharing the article on Twitter, I received an interesting question that I felt merited further discussion: How many of those now-non-homers turn into hits versus outs? That is a fascinating question because it potentially gets to the heart of why MLB dejuiced the baseballs in the first place. Baseball didn’t want to eliminate offense, per se; they just wanted to alter how it is generated, with more balls put into play rather than what they perceived as a recent over-reliance on the long ball. In short, if all of those newly-created non-homers are now other types of hits, then dejuicing the baseball might’ve actually had the impact MLB wanted. If they are now outs, then it’s just going to make life that much harder for batters.

Given the majors’ historically-low batting average this season — once again, I’ll point you to Brendan Gawlowski’s excellent piece on the matter — you can likely guess what happened: Outs are up. Read the rest of this entry »

Last week, I wrote about the Padres and how their usage of the infield shift stands out. To recap: They shift almost exclusively against left-handed hitters to great success, neglecting right-handed ones in the process. This decision is backed up by public research, which casts doubt on the efficacy of shifts against righties.

As a few of the comments noted, though, the Padres aren’t the most interesting subject when it comes to shifts. If anything, they’re conformists! The Dodgers and Rays, in contrast, are the rebels who defy convention by shifting more against righties than against lefties. We still don’t have a clear answer as to why. Leading up to this article, I did take a crack at the problem, and in the process, unearthed something about the Dodgers.

Before that, some context: Much of our discourse regarding the shift is focused on the dynamic between the hitter and team shifting against him. Kole Calhoun has a tendency to pull the ball, so the Dodgers have prepared this alignment. If Calhoun could go the other way, he’d earn himself a free knock, and so on.

But what about a version of the dynamic that includes the pitcher? By the same logic applied to hitters, if a pitcher could alter his approach to induce pulled grounders that are tailor-made for infield shifts, he’d probably be successful. We know pitchers can control the types of batted balls they allow to some extent: Last season, our Alex Chamberlain wrote about the relationship between pitch location and launch angle. As it turns out, a lower pitch will yield a lower launch angle compared to one located higher up, irrespective of pitch type.

Read the rest of this entry »

Seemingly in the blink of an eye, a month of baseball is behind us. With nearly 30,000 plate appearances taken and more than 18,000 batted balls put into play, a month of data is plenty to begin examining league-wide trends and to make some predictions for the rest of 2021.

One big question going into this season — and a topic already examined here by both Ben Clemens and Justin Choi — was what the impact of the new baseball would be on the overall offensive environment. As both Ben and Justin found and detailed, the new baseball is bouncier, yielding higher exit velocities than in years past, and also possesses more drag, as it is not traveling as far. I want to focus on that second point. If the ball isn’t traveling as far, we should be seeing fewer home runs hit in 2021 — and we are. But can we pinpoint just how many home runs will be hit this season? That takes a bit more guesswork, but before getting into that, let’s first see how April 2021 stacks up to prior seasons, as well as identify where exactly we lost those home runs.

Read the rest of this entry »

Pitchers are relying on their best pitches more and more. And why should they not? It makes all the sense in the world. Throwing a fastball 60% of the time just so that you can “establish it” is an outdated moniker that players and teams alike are reticent to follow. Take a look at the our season stat grid tool if you want proof that the most dominant pitchers in the league are increasingly relying on their breaking pitches. Select curveballs and you will see Julio Urías, Zack Greinke, Brandon Woodruff, Anthony DeSclafani, Dylan Bundy, Walker Buehler, Corbin Burnes, and John Means toward the top of the list. For sliders, that list features Tyler Glasnow, Lance McCullers Jr. (who is also throwing a new slider), Shane Bieber, a new and improved Jeff Hoffman, Freddy Peralta, and even Clayton Kershaw, whose slider is almost 45% of his pitch diet.

These are cherrypicked examples; not every pitcher on this leaderboard has been as productive as those starters thus far. But it does point to the idea that the best pitchers MLB has to offer are increasingly leaning into their best secondary offerings and have either continued to be successful or found another level in their production.

The idea of simply throwing your best pitch has become more in vogue in recent years. Back in 2017, Eno Sarris wrote that pitchers should try making breaking balls 80% of their total pitch mix. Part of the reason is that non-fastball pitches, specifically breaking balls, have gotten increasingly harder to hit; Ben Clemens wrote about this trend a couple of years ago. Even though fastballs have become harder to hit by virtue of increased velocity, pitchers are turning away from them in favor of other offerings.

This decision raises the question: Are pitchers successful with their non-fastball pitches because they use them less? The idea is that the main driver of offspeed or breaking ball success would be that hitters see them less, making them tougher to adjust to in a plate appearance. Theoretically, then, if a pitcher goes primarily to his secondary pitches, those pitches will become less effective on a per pitch basis. Is this true?

To investigate, I took every pitch type that was thrown at least 100 times in a season from 2018 through ’20. I took the year-over-year changes in pitch usage, swinging-strike rate, and run value per 100 pitches thrown for each season pair (where in both seasons the pitch was thrown on 100-plus occasions).

The first thing I wanted to look at was effectiveness based on changes in usage for each individual pitch type. The short answer to this is that there is little relationship between marginal usage change and marginal success in either of the two measures for any pitch type.

If anything, changeups and curveballs actually induce swinging strikes as a higher percentage of all pitches with more usage. That is the strongest relationship in this dataset, and it still consists mostly of noise. Based on the data, there is no evidence that pitchers should be dissuaded from throwing their best pitches more often, and that holds true for breaking balls, offspeed pitches, and fastballs.

Sure, you may argue, throwing any pitch a little more won’t have adverse effects on its effectiveness, but aren’t there diminishing returns? At a certain point, don’t you throw the pitch too often to fool the batter? To answer that, I placed each pitcher and pitch type pair into a bucket based on usage, then separated the bucket into increments of 10% (so the first consisted of pitches thrown between 0 and 10% of the time, the second 10% and 20%, etc.). I then grouped the pitch usages across the three seasons and looked for any potential deviations in effectiveness.

Again, these relationships are mostly noise. Even for pitches thrown upwards of 70% to 80% of the time (beyond which the the data is scarce), they should not lose any per-pitch potency by virtue of increased predictability.

For those of you skeptical that fastballs make up the majority of pitches and that this lack of a relationship may not be evident with breaking balls or offspeed pitches specifically, I have bad news for you:

As with run values, there’s no strong relationship between swinging-strike rate and usage.

As noted above, fastball usage is on the decline throughout the league. But using the data I collected from ’18 through ’20, it’s clear that pitchers aren’t all now throwing breaking pitches all the time.

The vertical lines represent the 50th percentile in that specific distribution. On average, pitchers using a certain breaking ball less than 30% of the time shied away from using the pitch more. On the other hand, breaking ball usage mostly increased for players who used it more than a cursory amount. That all makes sense: If you have a breaking ball you like to use (or are comfortable using), you’re going to throw it more; if you don’t have a strong breaking pitch, then you’re not going to be tossing it all the time even if it could theoretically be more effective.

Throwing a pitch just for the sake of throwing it is not going to fly in MLB in 2021. Pitches are thrown with a purpose: generating whiffs, or at least groundballs. This is one of the fundamental factors in the ever-increasing strikeout rate: Not only are pitchers throwing harder than ever, but they are also leaning on their best stuff even more. That’s while every one of those pitches is being optimized with the help of technology to generate maximum movement and deception. And that trend will not stop until there is evidence that a pitch will perform worse upon increased usage. Barring that, pitchers across the league will rely on the pitches they deem most dominant.

More than anything else, I’ll remember Carlos Rodón’s no-hitter for how it ended. Not when he hit Roberto Pérez in the foot — that was no fun, but perfect games end on nonsense all the time — but because he threw harder as the game went on, topping out at 99 mph on his 110th pitch of the game. It’s all the more impressive when you consider that he started the game in the low 90s.

Pitchers losing velocity as the game goes on is a phenomenon as old as baseball itself. That’s just how it works; throwing a pitch requires a ton of physical effort, and doing it 100 times will wear you down. If you’ve ever done repetitions of anything in your life, you can empathize. Rodón laughs at that fact of life, in a way that I think of as Justin Verlander-esque, and I was curious whether other pitchers follow the same pattern, particularly after Jacob deGrom popped a casual 101 mph fastball in the seventh inning of his latest start.

Using deGrom as evidence of anything is an iffy idea at best — the man is a unicorn, a pitching deity descended to earth. But Rodón is mortal, and he does it, so it’s hardly some unobtainable goal. I set out to see whether pitchers are adding velocity in later innings these days, and whether that addition has changed over time. Read the rest of this entry »

The strike zone doesn’t exist. Not physically, at least; it’s a rough boundary that varies based on how each umpire looks at it and how each batter stands. Catchers influence the shape, too; smooth hands can turn balls to called strikes, while cross-ups tend to do the opposite.

This year, the zone seems particularly amorphous — maybe it’s just my imagination, but I feel like I can’t turn on a broadcast without hearing about an inconsistent zone. Of course, hearing isn’t believing, and there are botched calls every year. Just because there have been some memorable ones this year doesn’t necessarily mean the overall rate of missed calls has changed. Let’s find out if it has, or if it’s merely imaginations running wild with the backdrop of fan noise.

For a rough idea of ball/strike accuracy, I went to Statcast data. For every pitch, Statcast records a top and bottom of the strike zone, as well as where the pitch crossed the plate. Armed with that data as well as some constants like the size of a baseball and the width of home plate, I measured how far out of (or into) the strike zone each pitch of the 2021 season was when it crossed the plate.

This data isn’t perfect. The top and bottom of the strike zone are approximated, and the plate isn’t a two-dimensional object, despite the fact that our data on it is represented that way. We aren’t considering framing. But we have previous years of the same data, which is great news. We can use the previous years to form a baseline, then see if this year’s data represents a meaningful change. And because we have a huge chunk of data, we can at least hope that framing comes out in the wash. Read the rest of this entry »

It is still early in the season, but one of the aspects of hitting that stabilizes relatively quickly is changes to approach. Swings are a more common occurrence, so the sample for these statistics grows faster than those that rely on an accumulation of plate appearances. So who seems to have made some changes in the early going?

To get an idea, I took all players who accumulated 250 plate appearances combined in the 2019 and ’20 seasons (I chose to group these seasons together because of the brevity of the pandemic-shortened campaign), then filtered by those who meet the qualified criteria in 2021. This leaves a sample of 159 hitters; each table includes the top and bottom ten players for each metric.

Read the rest of this entry »