Evaluating Early-Season Plate Discipline Breakouts by Kyle Kishimoto September 29, 2022 © Gary A. Vasquez-USA TODAY Sports Every year, the first few weeks of the season bring exciting and memorable performances from previously unheralded players. In recent memory, Trevor Story set the world on fire by hitting seven homers in his first six big league games despite not being on a top 100 prospect list that year. This season saw Seiya Suzuki quickly adjust to American baseball, posting a 234 wRC+ in his first two weeks. Steven Kwan saw 116 big league pitches before swinging and missing for the first time. And folks who aren’t regular readers of this site might have heard Connor Joe’s name for the first time when he had an OPS north of 1.000 through his first 15 games of 2022. But how do we know if these performances are sustainable? Story never reached those heights again but he still became an excellent big leaguer. Kwan is a Rookie of the Year candidate, but his teammate Owen Miller has fallen off after hitting .400 in April. Joe, meanwhile, has had a pedestrian .230/.334/.323 slash line since the beginning of May. We know that stats like OPS can take nearly a full season to stabilize, so how can we separate the Millers from the Kwans? This is where plate discipline metrics come in. Because the average batter sees nearly four pitches per plate appearance, plate discipline stats reach a reliable sample size much more quickly than the surface-level stats that are tracked on a plate appearance basis. The primary plate discipline stat we’ll be examining here is chase rate (listed as O-Swing% on the site). To my mind, chase rate is probably the best single stat to use when assessing a hitter’s swing decisions. Some hitters have outlier levels of plate coverage that allow them to do damage on pitches in specific spots out of the zone, but in general, chasing less is almost always better than chasing more. A quick glance at the relevant metrics will show you exactly why: Batter Results on Pitches In and Out of Zone Avg. Exit Velocity Slugging Whiff Rate In Zone 90.7 mph 0.564 17.8% Out of Zone 80.5 mph 0.215 42.6% For a variety of reasons, swing decisions are quite difficult to improve at the major league level. The average hitter’s plate discipline metrics don’t change by more than a few percentage points over the course of their career. Still, many of the most patient hitters in baseball have managed to make improvements. Mike Trout’s evolution from young phenom to the best hitter of his generation involved a steady drop in his chase rate throughout his mid-20s, while others make adjustments during their time in the minors that enable their breakouts as big leaguers. When we see a player go ballistic during the first couple months of a season, it’s exciting. But when these big performances are backed by noticeable improvements in the player’s swing decisions, they have much greater potential to be sustainable. So who were the biggest early-season plate discipline improvers of 2022? To answer this, I looked at every hitter with at least 200 plate appearances in 2021 and compared their chase rates that season to their chase rates through the end of May this season. The biggest improvers can be seen below: 2022 Early-Season Plate Discipline Improvers Name 2021 Chase Rate 2022 Chase Rate Through 5/31 Difference Austin Hedges 37.7% 28.1% -9.6% Taylor Ward 29.2% 19.8% -9.4% Dominic Smith 38.0% 29.0% -9.0% Andrés Giménez 44.4% 35.5% -8.9% Aledmys Díaz 37.9% 29.3% -8.6% Andrew Benintendi 34.6% 26.8% -7.8% Kolten Wong 32.1% 24.5% -7.6% Andy Ibáñez 33.8% 26.4% -7.4% Sam Hilliard 30.4% 23.6% -6.8% Christian Walker 32.2% 25.9% -6.3% Mike Yastrzemski 27.5% 21.2% -6.3% Salvador Perez 48.3% 42.0% -6.3% Lourdes Gurriel Jr. 37.3% 31.1% -6.2% José Iglesias 46.9% 41.0% -5.9% Gio Urshela 39.9% 34.1% -5.8% José Abreu 35.9% 30.2% -5.7% Min. 200 PA in 2021, min. 100 PA in 2022 through 5/31. Despite his excellent 24.7% chase rate through the end of May, you won’t see the aforementioned Steven Kwan here, as he debuted in the majors this season. Because minor league pitch data is largely unavailable for most players, we’ll solely be analyzing players who made swing decision improvements compared to previous major league seasons. There’s a wide variety of players on this list, but something they all have in common is that even when we look at a larger sample over the full season, they all have lower chase rates in 2022 than they did in ’21. Let’s take a look at a few of these players to see how their plate discipline development has impacted their overall results. One player who made Herculean improvements to his plate discipline was Taylor Ward. Ward was one of the biggest stories of the early season, putting up a Barry Bonds-like slash line of .384/.505/.744 with eight homers through his first 25 games. Equally impressive, though, was the fact that he walked just as much as he struck out; his chase rate of 17.9% ranked first among all hitters with at least 100 plate appearances over that stretch. ZiPS absolutely bought into the breakout, forecasting a 20-point increase in projected wRC+ as compared to previous seasons. And while his 1.249 OPS in the early season (aided by a .439 BABIP) didn’t last, he’s still kept up an excellent level of production in his first season as an everyday player. He has a 131 wRC+ with a very reasonable .318 BABIP, and at 3.2 WAR, he’s surpassed his ZiPS projection for the year. More importantly, Ward’s elite plate discipline gains have been sustained over the full season. He’s walked in 11.2% of plate appearances, and his career-best 23.4% chase rate ranks in the 93rd percentile of all hitters. According to Statcast’s swing/take leaderboard, Ward has created 23 runs by laying off pitches in the “chase” zone, pitches that are out of the zone but still close enough to make hitters swing often. Tied with Ward near the top of the leaderboard is fellow plate discipline improver Christian Walker, whose combination of swing decisions and raw power have led to his best season on record. Taylor Ward started the season with less than a full season’s worth of major league playing time under his belt; by making the necessary adjustments to his approach, he’s locked down a roster spot for the foreseeable future. But what about players who have been everyday big leaguers for the better part of a decade? Are they also capable of significantly slashing their chase rates? In the case of White Sox first baseman José Abreu, the answer here is yes. In his age-35 season, Abreu has the fewest home runs of any season in his career (including 2020) while posting a career-low isolated power. However, he’s on pace to post his best wRC+ in a full season since 2017. Abreu came into the majors in 2014 after lighting up the Cuban National Series (seriously, just look at his stats). In his early days with the White Sox, he was known as a free swinger with huge pop, clubbing 36 homers and finishing second in the league in OPS, while swinging at 41% of pitches out of the zone. Since then, he’s spent most years in the mid-30% range, including a chase rate of 36.4% in 2020, when he won American League MVP. After nearly a decade of big league experience, it was surprising to see Abreu’s chase rate go down to just 30% through May of this season. His current rate sits at 33.6%, the second-lowest chase rate of his career, while his 0.56 BB/K ratio is the best he’s ever posted. So how do we know these late-career gains are real? Let’s take a look at how he’s been pitched to this year as compared to previous ones: José Abreu Statcast Location Zones Heart Shadow Chase Waste 2015-2021 24.8% 40.6% 23.3% 10.5% 2022 25.8% 42% 22.6% 9.5% SOURCE: Baseball Savant It’s easy to hypothesize that Abreu has just been getting more pitches in the dirt (which are far easier to lay off of), but it turns out the opposite is true. Statcast’s attack zones were created to understand how hitters make swing decisions in four discrete regions, ranging from down the middle (heart) to nowhere near the zone (waste). Abreu has been seeing a lower proportion of pitches in the waste zone, but a similar number of pitches in the shadow and chase zones, where out-of-zone swings can realistically occur. All of this is to say that these improvements are no fluke. Abreu isn’t being pitched differently, he’s simply improved his swing decisions and is likely to finish the season with career-best strikeout and walk rates. Making these changes has proven to be especially helpful at Abreu’s age. We know that a hitter’s offensive production tends to crater when they enter their mid-30s, and many superstars have quickly become mere mortals after losing some of their speed, barrel control, and bat speed (see: Albert Pujols). Abreu’s 43 plate appearances per home run is the worst of his career (by a lot), but despite this, his overall production is even better than it was last year when he hit twice as many homers. Becoming a free agent going into their age-36 season is scary for many players, but Abreu’s improvements in the approach department may significantly lengthen his career. What about players who significantly worsened their chase rate in the first couple months of the season? Using the same method as before, let’s look at the players who swing at far more bad pitches than last season: 2022 Early Season Plate Discipline Decliners Name 2021 Chase Rate 2022 Chase Rate Through 5/31 Difference Oscar Mercado 26.7% 40% 13.3% Chas McCormick 28.2% 40.5% 12.3% Bryce Harper 29.4% 41.1% 11.7% Travis d’Arnaud 31.2% 42.4% 11.2% Joey Gallo 22.1% 33.0% 10.9% Tony Kemp 23.5% 33.7% 10.2% Raimel Tapia 36.7% 46.1% 9.4% Rafael Devers 36.1% 45.2% 9.1% Jesús Aguilar 32.0% 40.3% 8.3% Jeimer Candelario 32.3% 40.3% 8.0% min. 200 PA in 2021, min. 100 PA in 2022 through 5/31 There are many interesting players to analyze among this bunch, including Bryce Harper, whose newfound aggression at the plate may actually be beneficial, but there’s one guy I want to look at specifically because swing decisions are such a huge part of his profile – Joey Gallo. The quintessential Three True Outcomes player, Gallo has walked, struck out, or hit a long ball in over half his plate appearances every year of his career. As a hitter who puts few balls in play, Gallo’s ability to succeed offensively relies strongly on his ability to demonstrate patience at the plate. Last season with the Rangers and Yankees, Gallo had his best full season with a 122 wRC+ and a career-high 4.2 WAR despite hitting below the Mendoza line. His elite 18% walk rate was supported by a 22.1% chase rate, seventh-best among qualified hitters. In 2019, Gallo missed half the season but had a 144 wRC+ when healthy, and swung at just 24.2% of pitches outside of the zone. In the first two months of 2022, that number ballooned to 33%, near the league average rather than elite. As a result, his walk and barrel rates fell while his strikeout rate rose compared to his career averages. Gallo’s performance this year has significantly declined from last, slashing .166/.288/.364 while maintaining this elevated chase rate all year long. Going back to Statcast’s swing/take runs, there’s one key area where Gallo made a noticeable change. Last year, Gallo swung at 44% of pitches in the shadow of the zone, a region containing pitches within a few inches of the edge of the plate. This season, that rate has jumped to 55%. While this isn’t necessarily bad for all hitters, Gallo’s elevated whiff rate hurts him when he swings at borderline pitches. While the league as a whole comes up empty on 26.4% of their swings in the shadow area, Gallo whiffs 48.5% of the time. As a result, his chase rate has climbed without him doing any additional damage to pitches in the zone. These are just a few of the many players whose changes in production this year have been caused by an improvement or decline in their swing decisions. Whether conscious or not, changes in a player’s approach can often have career-altering effects. In Taylor Ward’s case, we’ve seen how a leap forward in approach turned a bench outfielder on the fringes of the roster into an above-average everyday regular, while José Abreu has used his newfound skills to prolong an already sensational career. The fact that sustained reductions in chase rates are so uncommon makes the stories of players whose careers were made or revitalized from swing decision improvements all the more interesting. While we like to imagine what many players would be like if they could make the right adjustments, only a select few can actually do it. All statistics through September 27.