Author: Jacob Mandel (Weinberg ’21)

 

As the number one prospect in the Cubs farm system for a long time, there was no question that Javier Baez was going to be an exciting talent. But after hitting .169 and striking out an abysmal 41.5% of his plate appearances in 2014 (the year he was first called up to the majors), it seemed clear that Baez would need to change his approach if he wanted to sustain any long-term baseball success. Anyone who remembers Baez’s rookie year can surely recall the tremendous amount of movement in his swing, with a lofty leg kick and violent loading of the hands. The next year saw Baez spending time in the minors with the Cubs for most of the season, where he worked on quieting his swing and improving his timing and plate discipline.

 

Still, Baez struck out on 24% of his MLB plate appearances in 2016, and 28.3% of his plate appearances in 2017. Nevertheless, his production increased, as he added 9 more HRs, 16 more RBIs, and improved his OPS from .737 to .796 in 2017 compared to 2016. However, despite posting a very solid 2017 slash line, it appeared as though Baez would never become an elite player if he couldn’t learn to be more disciplined at the plate. His aggressive approach yielded far too many strikeouts, which continued to hold him back.

 

The 2018 season saw Baez strikeout 167 times, or 25.9% of his plate appearances, swinging at a career high 57.7% of pitches and 45.5% of pitches out of the zone (both the second highest in MLB). Yet, Baez managed to finish in second place for the NL MVP voting after hitting .290 with 34 HRs, a league-leading 111 RBIs, and a 6.3 WAR (third highest for NL position players). So how can such an aggressive, undisciplined hitter do so much damage in the most competitive baseball league in the world?

The graphic above, provided by Baseball Savant, shows Baez’s stats on pitches that ended the at-bat against three different types of pitches. Breaking pitches are classified as a curveball, slider, knuckle, or other pitches with significant breaking movement, while Offspeed is classified as a changeup, forkball, splitter, or screwball. Part of Baez’s increased success in 2018 was his ability to hit the breaking ball, as much of his damage done in the 2018 season was against breaking balls.

 

According to Fangraphs, Baez swung at the first pitch 48.2% of times, which was a career high, and surely toward the top of the MLB (though, I could not find first-pitch swing rate rankings). It appears as though Baez is much more successful if he does not let the pitcher get ahead in the count, and having a more aggressive approach and putting the ball in play as soon as he gets a pitch in the zone does more to ensure this will happen.

As seen in the split stats provided by Baseball Reference, Baez posted incredible numbers when his at-bat ended on the first pitch or early on when he was ahead in the count. A plurality of his at-bats ended on the first pitch, though, where he posted some of his best numbers. The statistic sOPS portrays this very well, as it standardizes Baez’s OPS for each pitch count compared to the league average split OPS in the same situation to see how relatively strong of a hitter he is for each count (an sOPS of 100 is the league average). Most interestingly, Baez was a spectacular hitter in at-bats with counts with less than two strikes (with the exception of the 3-0 count, which has very few instances), but below league average with 1-2, 2-2, and full counts, and only slightly above league average on 0-2 counts. Perhaps if Baez improved his approach with two strikes, he could elevate his game even more to truly reach that elite MVP level.

 

One notable stat provided by Fangraphs is that only 47% of pitches Baez faced were fastballs, which was the second lowest in the MLB. In other words, pitchers likely pegged Baez as an aggressive fastball hitter and threw him more offspeed and breaking pitches as a result. However, despite facing so few fastballs, he finished with a career high 17.5 runs generated off of fastballs above average, crushing his previous high of 7.6, meaning he took advantage of the fastballs he did see. As seen above, this is likely a result of his approach at the plate, swinging so often at the first pitch, given that the most commonly thrown pitch to begin an at-bat is the fastball.

 

It’s also notable that 25.6% of pitches Baez faced were sliders (second most in MLB), the most sliders he’s seen in any season in his career thus far. While Baez didn’t fare either horribly or exceptionally against the slider, he still fared the best in his career with 2.9 runs generated against sliders above average. On the other hand, Baez did serious damage against the curveball, a pitch he faced 11.4% of the time (38th highest in the MLB). In the 2018 season, Baez was the league leader in curveball runs above average with 11.9, meaning he absolutely devoured the pitch. In past years, Baez had never even been positive in curveball runs above average, faring as a below-average curveball hitter prior to 2018! Much of Baez’s success in the 2018 season can be characterized by a newfound ability to effectively hit the breaking ball, with unprecedented production against the curveball and generally decent improvement against other breaking and offspeed pitches.

 

In terms of Baez’s quality of contact, his amount of hard contact rose from 29.1% in 2016 to 32.4% in 2017 and finally up to 35.8% in 2018, despite swinging the bat more often. This seems somewhat counterintuitive in that one would think somebody who swings the bat more frequently would tend to incur more weak contact as a result of swinging at more bad pitches, but this was not the case for Baez. Despite swinging at a much higher rate, even at pitches out of the zone, Baez was able to maintain a strong enough swing path to produce the most hard contact he had generated in his career. A further implication of his hard contact was that his home run to fly ball ratio rose from 19.7% in 2017 to 24.3% in 2018, while his line drive percent increased from 15.4% in 2017 to 22.1% in 2018.

As seen in the above graphic, even when Baez made contact out of the zone, his pure bat speed and range allowed him to make enough contact and put enough of the barrel on the ball to get on base. Even though his numbers tended to decline slightly out of the zone when he made contact, it’s still impressive how effective he was when hitting these pitches.

 

Overall, for the most part, Baez’s approach at the plate did not become any more disciplined than we’ve seen in the past. Yet his effectiveness nonetheless allowed him to post MVP-caliber numbers for a variety of reasons. For one, Baez learned to smash the breaking pitch, posting league-leading numbers against the curveball and improving his statistics against the slider and other offspeed pitches. Moreover, despite seeing the second-fewest fastballs in the entire MLB, Baez was still able to do considerable damage against the pitch, probably largely in part due to his exceptionally high swing rate on first pitches. Further, while swinging at such a high rate at pitches outside the zone, Baez was able to make enough hard contact on these pitches to yield impressive results. Lastly, Baez performed spectacularly when ahead or early in the count, but improvement on his approach with two strikes could push him into the highest echelon of hitters.

 

Sources

• https://baseballsavant.mlb.com/savant-player/javier-baez-595879?stats=career-r-hitting-mlb
• https://www.fangraphs.com/statss.aspx?playerid=12979&position=2B/SS
• https://www.baseball-reference.com/players/split.fcgi?id=baezja01&year=2018&t=b