Where has Christian Yelich’s power gone?

The Milwaukee Brewers appear poised to run away with the National League Central. As of this writing, they’re 6.5 games up on the fading Cincinnati Reds, 7.5 up on the offensively inept St. Louis Cardinals, and 8.5 ahead of the selling Chicago Cubs. At 56-41, they’re the only club in the division genuinely clear of the .500 mark, and one imagines just how far a rotation anchored by Corbin Burnes, Freddy Peralta, and Brandon Woodruff can go in a playoff series.

Interestingly enough, though, one of their offensive stalwarts hasn’t been quite the same player he was when they won the division back in 2019. Christian Yelich has been solid in many respects but is far from the power hitter he was when he finished as the NL MVP runner-up to Cody Bellinger that year (a season after winning it in 2018).

With Yelich failing to impact as much as he did in those previous seasons, though, the Brewers actually sit in the bottom half of the league in team ISO (.158) and team wRC+ (89). The majority of the offensive impact has come from Omar Narváez and Willy Adames, with the occasional contribution from Avisaíl García. Not a big surprise when you figure that Milwaukee was apparently opting for a defense-first approach to their lineup with the likes of Kolten Wong, Lorenzo Cain, and Jackie Bradley, Jr. Nonetheless, what could this team be if Yelich were producing at the level that he had become known for since arriving in Milwaukee?

What is happening with Yelich at the plate?

Yelich’s overall Soft% is up at 18.0, which would represent the highest of his career. On flyballs specifically, he’s fallen to a 48.6 Hard%. That wouldn’t seem bad, but it’s nearly a 20 percent drop from 2018 and a six-point drop from either of the two previous seasons. So it’s no surprise that his HR/FB rate has fallen to its lowest rate since his last season in Miami (16.2). That’s a far cry from anything he’s produced in Milwaukee in previous seasons. The power just isn’t there, with an ISO of only .139 for the season.

That’s not to say that he’s been bad offensively. His slash goes .244/.393/.383/.776. His wRC+ sits at 116, with a Chase% sitting in the 97th percentile (16.6) and a BB% in the 99th (18.7). For a guy who averaged a .307 ISO and hit 80 home runs between 2018 and 2019, there’s definitely a question as to what happened to the level of impact he was providing in the power game.

The simplest explanation, is quite obviously, health. Yelich fractured his kneecap toward the end of the 2019 season, which could have sapped some of the power in the 2020 sprint. This year, he started the season off with back issues, came back, went back on the IL after one game, and didn’t truly get his season started until the second half of May. But if anything is even remotely lingering, you could understand how a guy with massive power in his first couple of turns in Milwaukee suddenly lost it all.

But that almost seems too easy, likely as it could ultimately be. It’s a dramatic dip. And you’d think there would be more benefit to being as selective as he is. Is there something in the approach or in the swing that might indicate where the power has gone? Above all, this could perhaps be a matter of how teams are attacking him, both with their defensive configuration and the approach from opposing pitching.

Regarding the former, Yelich has been shifted against more than any other point in his career (57.1). He’s combated that fairly well, with an Oppo% that sits at 30.2, his highest since 2014. However, on the opposite field stuff, he’s experiencing even less success than he is in the bigger picture. His Hard% sits at 35.7, with an ISO of .071. He has yet to hit an oppo homer in 2021. For comparison, his 2018 and 2019 seasons featured averages of 49.2 Hard%, a .386 ISO, and a total of 17 home runs. When he pulls the ball in 2021, though, he makes hard contact at a 45.8 clip and a .255 ISO. So there may be a reluctance to pull the baseball, given the looming presence of the shift, and he’s struggling to do so effectively.

Just as likely, though, is how opposing pitchers are attacking him. Yelich’s Zone% is back up after a couple of seasons in which pitchers were approaching him far more carefully. In 2019, that Zone% was at just 35.9 before a 36.0 mark in 2020. But in 2021, it’s crept back up to 39.4; that isn’t quite to where it was before his MVP season but is getting closer. With that, Yelich has shown more of a willingness to swing at pitches inside of the strike zone, despite a very low overall Swing% of 38.2. At the same time, his Z-Contact% is at just 81.9, which is almost six percent lower than his career norm.

Fastballs represent a particularly interesting case. Pitchers have gotten back to throwing a higher volume of fastballs against Yelich inside of the strike zone:

Against fastballs, Yelich has failed to generate much barrel contact. His Barrel% is at just 5.7, according to Baseball Savant. At his height, that figure was at 14.8 against fastballs. So when he does swing, he’s not doing nearly the damage that he did in those outlandish 2018 and 2019 seasons.

And when he does swing is a fairly significant issue for Yelich right now. While his overall Swing% is up a touch from last year, it’s still far lower than it was when he was hacking at a 44.0 or 45.2 percent rate in either of ‘18 or ‘19. It’s led to his highest walk rate ever (18.7) and has helped him to cut down on his 30.8 K% from 2020, but there is such a thing as being too patient. From someone far smarter than I am, Justin Choi at FanGraphs has an outstanding writeup on the balance between the approach and the Zone%, indicating some fairly large issues for Yelich’s standing as a hitter right now.

Choi raises some important questions:

But as far as adjustments go, raising his aggression to match that of pitchers, who are adhering to both a new and old book on himself, is a simple one. As Yelich recuperates, the various components of his game are likely to come together. It’ll be interesting to observe how he and opposing pitchers adjust against each other over the course of an entire season, engaging in a dance of zero sums. How high will Yelich’s zone rate climb? At what point does he swing enough for pitchers to change course and offer more balls instead?

Within that piece, Choi also circles us back to the original explanation: health. There could certainly be a reluctance to swing in hopes that he doesn’t aggravate his back injury. So instead, it’s resulted in an overly patient approach, less hard contact, and, ultimately, a player that looks far more like he did with the Miami Marlins than he has with the Milwaukee Brewers. In any case, there’s a likelihood that remains that we could see Yelich’s return to form in the longer term. The more comfortable he feels, the more aggressive he may get. On the other hand, a wildly patient approach like this could be difficult to work out of mentally, and it’ll be interesting to see how long it holds Yelich back from making noise in the power game again.

Randy Holt is a contributing writer for Beyond the Box Score. You can follow him on Twitter @RandyHolt42.