How to Tell if a Breakout is Legitimate
With the 2019 season finally kicking off, there will be plenty of speculation of which early season performances are sustainable and which players will regress back to what is usually expected of them. I wanted to look back towards a couple past examples of breakouts and dive into what indicators can help show which players are legitimately improved at the plate, and which players seasons come with a little bit of luck and are followed by a whole lot of regression.
First, I would like to take a glance back at a real breakout and what signs pointed towards sustainable success. Didi Gregorius has a very interesting career arc that is a little more complicated than it seems on the surface. Gregorius came out of the gates hot when he made it to the majors despite a below average bat profile in the minors so once he started to slow down the Diamondbacks did not have too much faith in his ability to produce in the future. In the first half of his rookie year, he had a 102 wRC+ with an above average glove which immediately made him one of the more valuable shortstops in the league if he could keep it up. However, quickly-diminishing plate discipline skills, along with a poor-showing power, left Didi outside of the Diamondbacks future plans as Nick Ahmed and Chris Owings slowly began taking innings in the middle infield. With a trade to New York to replace Derek Jeter came some intense pressure and Gregorius responded with some serious offensive improvements. Didi made some extreme changes to his approach that led to fewer strikeouts and walks. He also cut down some of his fly balls from the diamondbacks in favor of a more groundball approach in New York which may have helped increase an extremely low .257 BABIP. However, what the Yankees surely saw when they acquired Gregorius was extreme pull and opposite field splits. Gregorius had a 25 wRC+ on balls hit the opposite way in 2014 with a 37 wRC+ on balls hit up the middle and a 222 wRC+ on pulled balls. Exactly as you would expect to happen, Didi went to the Yankees and immediately began to pull the ball more from 33% in 2014 to 39% in 2015. There are some fairly obvious mechanical adjustments, as the Yankees had Didi introduce a bigger leg kick and had him stand up straight, in hopes to help free up his hands to pull the ball more. Here is a look at the difference:
However, the swing change to pull the ball more still had room to improve, especially since his groundball percentage increased with the Yankees. Didi’s wRC+ increased 9 points, 10 points, and 14 points in each of his offseasons with the Yankees, so it is clear that he continues to make adjustments to keep getting better. In each of his first 3 seasons with the Yankees, his average launch angle increased while his exit velocity remained relatively constant. His strikeout rate decreased slightly, along with slight decreases in his walk rate. More power from Gregorius, along with stable contact and discipline skills, meant more productivity from the plate. However, 2018 saw Didi take a new turn with his approach. With an increasing launch angle and increasing fly ball rate, Didi was hitting under the ball 35.5% of the time, which is well above the league’s rate of 25.5% of the time. So, Gregorius realized his over adjustment and his average launch angle in 2018 dropped for the first time as a Yankee, down to 15.6 and his rate of hitting under the ball dropped to a manageable 31%. That is not all, however, Didi’s walk rate increased significantly to 8.4% and for the first time as a Yankee, he had above average results against fastballs, with a .358 wOBA. His .056 increase in wOBA against fastballs was the 10th largest in baseball. Perhaps Didi got stronger and increased his bat speed. Along with a better ability to catch up to the fastball, he also increased his average exit velocity to a career-best 86.5 MPH and his Max Exit Velocity increased to another career high of 109.4 MPH. So, with increases in both his approach at the plate along with potentially new physical abilities, these were and still are signs of a legitimately improved player.
Now for a counterexample, Tyler Naquin came in 3rd for the AL Rookie of the Year voting in 2016 with a .296/.372/.514 triple slash in 116 games for a World Series runner-up Cleveland Indians team. On pace for a 20 homer and 8 stolen base season with that slash left Naquin seemingly as a shoo-in to start in center for the following seasons. Naquin was in good company in the rookie class, as he was just behind Michael Fulmer and Gary Sanchez while being trailed by Chris Devenski, Edwin Diaz, Nomar Mazara, and Tim Anderson. However, we have not seen that progress that many expected for the highly regarded rookie as he failed to break camp in 2017 and has been on the shelf with injuries since then. Looking at his 2016 season, there are some telltale signs that his performance was likely a fluke that was fueled by luck. The first statistic that pops out is a .411 BABIP that helped lead to a .292 batting average despite a high 30.7 strikeout rate. That .411 average was higher than any minor league season Naquin ever had and BABIP usually declines from the minors to majors. Further, despite ranking 60th in average exit velocity, Naquin was ranked 243rd in sprint speed which does not point towards a high BABIP. With a wOBA of .374, he outperformed his xwOBA by .043 which was the 11th largest differential in the league (min. 250 PA) which includes some expected high BABIP performers Byron Buxton, Dee Gordon, and Trea Turner. Naquin’s biggest differential came on fly balls where his wOBA outperformed his xwOBA by .106. This is displayed in Naquin’s home run to fly ball ratio which finished at 22.2% or 19th in the league despite a 61st ranked exit velocity on fly balls and line drive. For reference, Naquin is sandwiched by Joc Pederson, Miguel Cabrera, and Giancarlo Stanton in that ratio and those three ranked 6th, 7th and 8th in exit velocity on fly balls.
The outcome of these batted ball events suggests plenty of luck during Naquin’s season. While he displayed some impressive and unexpected power numbers as a rookie, it came at the serious cost of contact skill as his strikeout rate ranked 9th in the league. The next highest strikeout rate to match Naquin’s 133 wRC+ in 2016 was Freddie Freeman with a significantly lower 24.7 strikeout rate. So as Naquin reached the majors, he sacrificed some contact ability to produce more power and some luck on his batted balls allowed this approach to yield successful results. However, this one year fluke did not point towards long term success. When demoted to the minors in 2017, Naquin lowered his strikeout rate significantly back down to 22%, but his power dropped as well, as his AAA season failed to live up to his rookie season in the majors. In an albeit small sample size of about 220 PA in the majors since then, Naquin has sported a 23% strikeout rate with significantly reduced power numbers that coincide with a drop in launch angle and exit velocity. Since that rookie season with 8.5% barrel rate on batted balls, Naquin has only barreled up 3.75% of batted balls, presumably in an attempt to retain contact skills and reduce strikeouts.
Naquin’s skillset displays a common red flag which is sacrificing contact for power. While Naquin, a long time on base and contact outfielder, showed increased power as a major leaguer, it is important to look at the peripherals to determine the sustainability of that power. Naquin did not develop power to go along with his career contact approach, but he developed it at the cost of his normal approach. While this change happens with plenty of players, Naquin stands out because his batted ball luck made it seem like perhaps this approach could be successful, however, Naquin has failed to be a productive offensive player at the major league level since then. If Naquin can tap into the power without losing his contact skills, perhaps we will see him return to the level of play we saw in 2016, but until then, plan on seeing a 4th outfielder or a AAA depth outfielder for the Indians.
So finally, here is a player who broke out last year and is still followed by doubts of legitimacy to his skill level and ability to continue producing. Max Muncy had a legitimate breakout this past season. A trade to the Dodgers brought with it one of the highest barrel rates in the entire league at 16.9 %. The biggest change with the Dodgers was a huge increase in aggressiveness at the plate. While Muncy held a similar swing rate as he had with the Oakland Athletics, he sacrificed contact for power. While his strikeout rate increased from 18% to 27%, the versatile infielder saw a huge increase in power in Los Angeles. Muncy took the route that so many players are taking to increase effectiveness at the plate and sacrificed contact and a ground ball approach in favor of power with more swing and miss in their game. Muncy’s 51% groundball rate in 2016 drastically fell to 34% with the Dodgers. With the Athletics, he managed only three barrels in 89 batted ball events, which is more or less unplayable lack of power for a first baseman. What reflects this increase in aggressiveness in Muncy’s approach is his ability to hit the inside pitch. Even in 2016 as a 38% below average hitter, Muncy could crush the outside pitch. Muncy had an average Exit Velocity of 91.1 MPH and a .394 xwOBA on outside pitches in 2016 compared to the league averages of about 90 MPH and .323 xwOBA. Taking a look at that 2016, Muncy was only successful hitting the outside pitch when pulling the ball or hitting it back up the middle. Muncy actually had a below average .295 xwOBA when hitting outside pitches the opposite way. So, if Muncy’s sole production was coming from pulling outside pitches, you would expect that perhaps he was struggling with inside pitches which is exactly what happened. Muncy finished the 2016 season with a .181 xwOBA on inside pitches which is extremely poor especially for a power hitter. His average exit velocity on inside pitches was a measly 74.7 MPH which explains how the Dodgers’ all-star was designated for assignment by the Athletics.
So when acquired by the Dodgers, Muncy had shown some quality pop on outside pitches without the ability to be effective when pitchers came in on the plate. When looking to see if this past year was repeatable success, we need to look at where Muncy made sacrifices in order to find that power stroke. For starters, Muncy increased his average exit velocity on inside pitches to 90.1 MPH for a .388 xwOBA which is a monumental increase from his time with the Athletics. However, it can be easy to just focus on either outside pitches or inside pitches so in order for Muncy to remain successful he would need to continue the same success on those outside pitches that he crushed back in Oakland and that is exactly what happened as he kept his exit velocity on outside pitches up at 90.4 mph. With a more aggressive approach at the plate, Muncy was able to fix a hole in his swing while remaining successful at the same things he did in Oakland. Now, Muncy did introduce more sing and miss to his game that came with a huge increase in strikeouts. However, with more strikeouts, Muncy made the trade-off worth it by offsetting strikeout with significantly more power on pitches over the heart of the strike zone. In 2016, Muncy had only a .143 ISO on pitches over the heart of the plate. So while he was avoiding strikeouts, he did not make effective use of the extra contact that he made. Meanwhile, in 2018 Muncy saw that number skyrocket to .533 ISO which ranked second in the MLB behind MVP candidate Jose Ramirez. Muncy’s new approach allowed him to do more damage on the fewer pitches he did make contact with that led to 9.4% Barrel/PA which ranked just behind Mike Trout as the 9th best rate in the league. While Muncy did overperform his overall xwOBA by .013 in 2018, the peripheral numbers that outline his approach change point towards a legitimate breakout that is sustainable for the Dodgers’ infielder. Finally, just for good measure, we can compare Muncy to some of the other hitters with a similar batted ball profile using Baseball Savant’s Affinity tool and see some of the great hitters in the game.
Of this group, Muncy has the second best walk to strikeout ratio as well as the third lowest BABIP. These are two measures that prove once again that there was not a whole lot of fluke to Muncy’s 2018 season, but actually a true breakout season for the Dodgers. So while there may be some natural regression for Muncy from his campaign as one of the game’s best hitters when it comes to hitting left-handed pitching and a high home run to fly ball ratio, Muncy should remain an elite hitter in the middle of a loaded Los Angeles lineup.
All Data Courtesy of Fangraphs and Baseball Savant
Feature Image Courtesy of @ensign_beedrill, Wikimedia, and Dandrea Photography