I'm Back. Will Christian Yelich Be?

Christian Yelich has certainly had one of the more interesting careers; from being drafted by the then Florida Marlins out of high school, to developing into a solid piece for a contending Miami team, only to be shipped away to Milwaukee where he absolutely broke out and became one of the best hitters in the game. Yet, after his first two years on the Brewers where he was seemingly on another planet, he regressed heavily in 2020 and 2021, below his Miami days. Put simply, he has never performed this poorly. How could such a sudden crash down to earth have happened? What went wrong? And does Yelich have the ability to fix it?

First, let's go into why Yelich suddenly broke out on the Brewers in the first place. And the answer is simple: power. Miami saw him hit 59 home runs, with a .142 ISO, and slugging .432 from 2013-17. In his first two seasons in Milwaukee, he slugged .631 with 80 bombs and a .304 ISO. This astonishing increase in power can be attributed to his ability to barrel a baseball. Since statcast began collecting batted ball data in 2015, we have to omit Yelich's first two seasons in Miami. Yet, his final three still show us a 2.7 degree launch angle and 6.7% barrel rate. His first two seasons in Milwaukee he raised his launch angle to 7.9 degrees, and a 13.9% barrel rate. Similarly, Christian Yelich is the perfect example of why plate discipline matters. Plate discipline is a trait that players either have or don't have, while power can clearly be developed over the course of a career. Essentially, when looking at young talent, plate discipline trumps power. One can be instilled, the other can't.

Again, one thing Christian Yelich has constantly been defined by is his plate discipline. In the minor leagues he consistently put up double digit walk rates and low strikeout numbers, and that continued going into his major league career. In his five year stint with the Marlins, Yelich had a walk rate of 10.7%, paired with a strikeout rate of 20.6%. Nothing crazy, yet solid numbers nonetheless. This was also supplemented with a .369 on base percentage, which again, is solid but not out of the ordinary. In 2018-2019, his plate discipline continued to be good, as he had an identical strikeout rate of 20.6%, and upped his walk rate to 12.0%. This raised his on base percentage for those two years all the way up to .415. Yes, some of the increase in on base percentage is attributed to his improvement in power, as mentioned before, but it also has a lot to do with improvements in plate discipline.

2020 was a weird year for just about everyone, and Yelich was no exception. No fans, worries about Covid-19, and a much smaller sample size of games created a year of anomalies. Yelich had an unbelievable 18.6% walk rate, yet had a gross 30.8% strikeout rate. Many, including myself, figured he would return to his 2018-19 numbers for the 2021 season, which he didn't quite accomplish. In 2021, he had a 14.7% walk rate, and a 23.8% walk rate. Significant declines in each statistic, but still high relative to the rest of his career. Something below the surface had to have changed between 2019 and 2020.

Interestingly enough, it seems as though Yelich made an effort to become more selective with his pitches in 2020 and 2021. This doesn't quite make sense; he already had good plate discipline to begin with, why make any kind of change? The statistics, as always, back this up. From 2019 to 2020, Yelich's swing rate dipped from 45% to 34%, his meatball swing rate dropped from 81% to 66%, and his first pitch swing rate had the sharpest decline: from 29% to 13%. Sure, this might've helped in some facets--Yelich had his chase rate drop from 27% to 17%, thus he swung at less pitches outside the zone. Yet, by taking an astonishing number of pitches down the middle, bad things happened. He let good pitches go to the wayside, missing out on opportunities to barrel the baseball, and instead getting a bunch of called strikes and digging himself into two strike counts. And somehow, his whiff rate on 2020 reached 33%, compared to the 28% from the year prior.

Yet again, we must also look at 2021. The year 2020 brought only a small sample size to the table, and Yelich saw way more pitches in 2021. In 2021, Yelich's whiff rate went back down to 25%, displaying that the 33% peak from 2020 was probably a fluke. But his swing rate, meatball swing rate, and 1st pitch swing rate in 2021 were 41%, 74%, and 22%, respectively. All higher than the 2020 numbers, but still significantly lower than his statistical greatness in 2019. His chase rate also remained around the 17-18% range in 2021. Put in simpler terms, Yelich is continuing to do something vastly different from his MVP days, for some odd reason. These visuals (brought by Baseball Savant's swing-take metrics) may help put it into perspective:

Here we see Yelich's final season in Miami, 2017. He's doing a terrific job taking bad pitches, and drawing walks, yet is hindered by his inability to recognize pitches in the zone. On the far right it displays the run values of swinging at pitches in a particular zone, versus run values of taking pitches in that particular zone. Yelich takes too many pitches in the heart of the plate (-10 run value on takes) and can't hit pitches on the shadow of the plate (-15 run value on swings). We'll see this improve upon his arrival to Milwaukee.

Here's Yelich's MVP season, his first year with the Brewers. What's incredible to me is his improvement on pitches within the heart of the zone. He went from -6 swing runs to +43 swing runs. This is probably due to his increase in swinging at both meatballs, and first pitches, as well as, of course, his development of power. And he retained his ability to take pitches outside the zone, while also improving his work on the shadow of the plate. This brings up that same interesting point mentioned earlier. Plate discipline is an instinct--it can't be taught. It can't be changed, so upon big league arrival, what a player has is what a player will always have in terms of plate discipline. In Milwaukee, he didn't necessarily change his plate discipline upon arrival. His ability to generate walks and avoid strikeouts remained the same--his strikeout and walk rates mostly remained constant between Miami and Milwaukee. What he improves was his actual ability to hit the ball, as seen by his ability to kill pitches down the middle and his increase in power.

Nothing truly of note happens between the 2018 and 2019 season for Yelich, as seen here with his 2019 swing-take visual. He gets slightly better with pitches outside the zone and slightly worse on pitches within the zone, but nothing to write home about. He is still an MVP caliber hitter at this point.

In 2020, Yelich's swing rates plummeted. A decrease by 13% in swinging at the heart of the plate, 14% on the shadow, and 10% in the chase zone compared to 2019 (he remained the same on waste pitches). Now, the main thing that also sticks out is the drastic change in 2018-19 run values for the heart of the plate versus 2020. I was ready to blame his inability to swing at pitches in the heart of the plate, but what's even more of a head-scratcher is that his take runs remain the same compared to prior years, it's actually his swing runs that take a dip within the heart of the plate. His swing runs went from +29 to 0 in one season. However, I do find this to be somewhat of a fluke. Number 1, Yelich's BABIP dropped from .355 to .259 from 2019-2020. That's almost 100 points in one season, and we know BABIP is generally regarded as outside the hitter's control, pointing more to a luck factor, or lack thereof. And number 2, Yelich still maintained his high quality of contact stats--his barrel rate was still in the 12-15% range (same as 2018 and 19), and his hard hit rate actually increased by a few percentage points from 2019-2020. The bottom line is, Yelich was plagued by bad luck in 2020, causing his stats to be severely deflated, as he couldn't do anything no matter how hard he hit the ball. However, his change in plate discipline only added insult to injury, which was another main cause to his stat deflation.

Finally, we reach 2021. Again, his swing rates increased, but are still not near where they were at his MVP caliber stage. His run values outside the strike zone are actually the exact same as 2018, and his shadow is in the range of those 2018-19 seasons. But alas, the heart of the plate run value continues to decrease at an alarming rate. And this time, it isn't due to bad luck. Yelich's BABIP for 2021 was .321, thus returning near his career mean. In terms of quality contact, his barrel rate dropped from the 78th percentile in 2020, to the 35th percentile in 2021 (it was the 97th and 96th percentile in 2018 and 2019, respectively). This is probably due to his launch angle decreasing to 2.8 degrees, a stat that peaked at 11.5 degrees in 2019. His ISO also dropped from .342 to .125 from 2019-21. Yelich's power is not only much worse than the rest of his Brewers' tenure, it is actually even worse than his days in Miami, back when power was the one tool he didn't yet have. So without bad luck to blame, we must return to the plate discipline discussion.

In 2021, 16.9% of pitches thrown to Christian Yelich ended in a called strike. This is compared to the 13.9% of called strikes Yelich saw in 2019. And sure, being selective even within the strike zone can be viewed as a good thing. If a hitter struggles with inside pitches, they shouldn't attempt to hit inside pitches and make weak contact (unless there's two strikes in the count). Before two strikes, they should swing only at what they can hit: at what they can barrel. Let's look at one more pair of visuals (also brought by Baseball Savant) to prove that Yelich is being negatively selective, rather than positively selective.

Here's a chart displaying the regions in and around the strike zone that Yelich had the most barrels in for 2021. Clearly, he can hit pitches down the middle, pitches middle away, and low pitches on the heart of the plate. So theoretically, if he was positively selective, he would swing most at pitches in those red barrel regions, and he would leave inside pitches and other bluer regions alone until two strike counts.

Now, this graphic shows the percentage of total pitches that ended up being called strikes for each region of the strike zone. For some odd reason, the two boxes with the highest percent of called strikes are the same as the two boxes with his highest barrel rate (apart from straight down the middle). Simply put, Yelich is watching the pitches he can hit best go right down the plate without even taking a swing at them. What he should be doing, is swinging at those pitches and barreling them, as well as taking more pitches on both the higher and inside parts of the strike zone, since he can't hit nearly as well in those areas.

Christian Yelich's fall from grace is unbelievably fascinating to me. It shows how hitters are almost nothing without the proper plate discipline, and removing it or attempting to alter it can completely knock a hitter off kilter, destroying many other attributes of theirs (including power). Maybe it's all mental, maybe it has to do with his knee injury at the end of 2019, maybe a hitting coach gave him wretched advice, or maybe it is a complete anomaly. But either way, Yelich messed with his plate discipline by becoming too selective, and he is paying the hefty price. It's definitely possible he returns to form, but at age 30, and being two seasons away from the ideal plate discipline he once was at, he must return to his old swing patterns before it's too late.