What's Happened to Christian Yelich?

On top of hitting more lower-angled ground balls than at any point in the season, Yelich has also been getting alarmingly increased numbers of swing and miss, with a whiff rate of 21% rising to 27.4% in August and 36.4% in September. Of more issue, however, is that his exit velocity dropped off significantly. His lowest recorded monthly exit velocity this season, coming into August, was 91.8 mph and was up to 94.4 mph in July. In August, this cratered to an average of 86.3 mph. Yelich has always hit the ball hard, even when pounding it into the ground, so this is particularly concerning and a notable outlier from anything he has previously produced for the Milwaukee Brewers.

Taking all this into account, it seems fairly clear that this is not an outburst of poor luck like the one he had in May, and in fact, all the ingredients are there for a sizeable slump in form.

What’s changed?
In short, tension. Let’s look at a few still frames, and there’s one very noticeable difference among them.

Yelich above is hitting a home run off Miles Mikolas in 2019. In and around the release point, you can see how upright and relaxed Yelich’s posture looks. His languid, free-flowing swing loses a lot of power when he forces it, so being limber is key. It’s one big reason why I believe he can go on short spurts of vintage performance, where he loosens up and relaxes before tightening up again when something goes wrong.

Here he is in July 2023, remarkably similar in the initial stance. During this period, he was crushing balls at a rate not seen since 2019, and you can see why with the similarities between the images at the point of release. Pay close attention to where his right elbow is here and the stance when looking at an image from Saturday’s game.

And now for the weekend, lining an RBI single against Aaron Nola for his only hit so far in September, but you can already see just how much more hunched up and crouched over he is at the plate, eliminating a key source of his power. Crouching over to this extent reduces the amount of torque generated by the hips, potentially the source of his dip in exit velocity. His right elbow is pointing almost down toward the ground as a result, instead of the 45-degree angle he has during his hot stretches in both 2023 and 2019, which significantly impacts how he can get the bat into the hitting zone, as well as tensing up the whole shoulder muscle as a result. 

Can He Rebound Again?
Absolutely. While the results may be chalk and cheese, the only noticeable difference is his upright stance at the plate and its lead-on effect on the tension in his shoulder. It’s getting in the way of him timing the ball as he would like and timing his swing effectively, making it a little more jerky and wrist-oriented at the end. He can’t quite get the bat out in time and has to flick his wrists to get it in the zone on time, resulting in far greater variance in his contact quality. Any sporting movement in the world, to be repeatable and explosive, has to be as tension-free as possible, something Yelich's swing in August has felt the ramifications of.

With the hitting coaches the Brewers have, it stands to reason that a simple fix and tweak could set him on a tear similar to July, at which point, the Brewers offense becomes truly fearsome. He has so much power in that bat waiting to be unleashed and could carry the Brewers through the postseason in a hot stretch.

As always, Yelich is a tantalizing watch, and how he performs will have a close connection with how the Brewers finish out the season.