Checking in on Jo Adell’s Much-Improved Strikeout Rate

In the years after being drafted by the Los Angeles Angels 10th overall in 2017, Jo Adell was one of the most exciting prospects in baseball. He spent the next few season flying up prospect lists around the industry; at FanGraphs, Adell ranked 66th overall in 2018, 11th in 2019, and fourth going into 2020. Last year, he made his much-hyped debut but it went about as poorly as 38 games and 132 plate appearances can go. He struck out a shocking 41.7% of the time, with an abysmal 29 wRC+. When combined with his surprisingly poor defense, he ended up being the least valuable player in baseball last season.

Adell spent his offseason retooling his swing and sharpening his defense. The Athletic’s Fabian Ardaya had this to say about Adell’s changes:

“One day in the cage, he started to cut things down. He held his hands higher, reducing their movement before the pitch. He focused on putting his body in a position to consistently be on time and athletic, rotating through his hips to generate power instead of attempting to force it. He ditched his leg kick, opting for a toe tap that gave him more of a window to stay on time and on plane with a flatter overall approach.”

Adell spent the first three month of the season continuing to work on his approach in Triple-A. His strikeout rate was still poor (29.2%), although it improved slightly compared to his 2019 Triple-A stint (32.6%). But we also began to see a new level of power from Adell; he hit 23 homers and put up a .302 ISO in 339 plate appearances to go along with a 121 wRC+. By August the Angels had seen enough to give him another crack at the highest level.

Adell hasn’t exactly lit the league on fire since his return; he boasts a 95 wRC+ and below league-average power (.158 ISO). More recently however, he’s looked better, with three homers already this month. And when I saw what was going on with his strikeout rate, I thought it was time to take a closer look at what he’s been up to.

Adell’s K% is all the way down to 23.1%, nearly half of what it was in 2020 and quite a bit lower than what he was doing in Triple-A this season. In light of his work on his swing, I want to start by looking at Adell’s current swing and seeing how the changes he’s made could be improving his ability to make contact.

Let’s start with a view from the front:

It’s quite a different look, from his hands down to his legs. His hands start higher and stay high, even through his load. The leg kick is also quite a bit different. Ardaya’s reporting from earlier references a toe-tap in lieu of Adell’s big leg kick — clearly visible in his swing from spring training — but now it seems that the leg kick is back, albeit in a less extreme form than it took last season.

The following side view really highlights how different his base is compared to last season:

He’s adjusted the way he balances on his back leg as he’s loading. He’s no longer in a slightly bow-legged position during his leg kick. This side view also shows that his leg kick is not just lower but also angled quite differently. Last year, the number of moving parts in his lower half seemed ripe for a lack of consistency. To me, the way he uses his lower half now looks a lot smoother and fits better with his upper half. Notice how his new leg kick is in better lock-step with the movement of his arms; his hands are moving back as his front leg is. His hands no longer loop downward during his load, which gives him a quieter transition between his load and the start of his hands driving toward the ball.

Now here’s a snapshot at the height of his leg kick:

One thing that jumps out when looking at that side-by-side is Adell’s more wound-up bat head from this season. It’s certainly not my favorite part of his new swing as it adds to the length of his bat path, but his implementation actually has a pretty smooth transition into his slight-uppercut swing. Adell has also wrapped his bat like this before, as Eric Longenhagen noted in his prospect write-up last year, so it’s something he has had prior success with.

We’ve seen the new swing in action and it appears to be smoother and have better balance. Both factors could be driving his decreased strikeout rate. Let’s take a closer look at his plate discipline numbers now that we have his new swing in mind:

Jo Adell’s Plate Discipline
Season O-Swing% Z-Swing% Swing% Contact% SwStr%
2020 35.4% 71.7% 50.8% 60.8% 19.9%
2021 40.0% 74.4% 53.8% 72.4% 14.8%
League Average 31.2% 68.8% 47.1% 76.0% 11.3%

When you see someone’s K-rate drop as much as Adell’s has this year, you expect to see some more eye-popping changes when it comes to his swing decisions. In fact, he’s actually swinging at pitches outside the strike zone at a higher rate than last year. Adell is clearly making a lot more contact when he is swinging, though, and his Contact% and SwStr% have both improved a lot. In terms of swinging strikes, he’s gone from being in Javier Báez territory down to something resembling Brandon Crawford, or from having one of the worst swinging strike rates in baseball down to a manageable, albeit still high, level.

Fastballs in particular are an area where he’s seen a lot of improvement this season. He had a huge issue with four-seamers last year, a pitch he sees more than any other type; he swung through a league-worst 26.2% of them. When a hitter is so much worse at making contact against fastballs compared to league average (10.6%), it’s a pretty clear sign that his swing is ill-equipped to deal with velocity. This year, Adell’s swinging strike rate against four-seamers has improved to 19.0%. That’s still quite high but it’s at least within striking distance of other successful hitters — Rafael Devers swings through 19.5% of fastballs — even if there aren’t that many successful hitters in that range. To take his fastball improvements to the extreme, look no further than how he has done against high-velocity:

Jo Adell Against Pitches 96 mph or Greater
Season wOBA EV SwStr%
2020 .144 93.5 27.3%
2021 .462 93.6 13.2%
League Average .296 89.3 12.3%
SOURCE: Baseball Savant

The samples in these buckets are annoyingly small at this point in his career, but it’s easy to see how drastically different Adell looks against heat. Whether it’s the opposite field homer he hit Wednesday off a 97 mph fastball above his belt, or the mammoth grand slam he launched a couple weeks back (see both below), his new swing has him much better equipped to handle the type of fastball that is increasingly common at the big league level:

Adell’s plate discipline numbers and results against fastballs lead me to believe that his improved strikeout rate is the result of his new swing being more contact-oriented, rather than an improvement in his underlying decisions on what to swing at. In a perfect world, he would improve in both of those areas but it’s still a great sign that he’s seeing better results after making such a drastic change. The balance he’s creating with his new leg kick and the lack of hand drop in his load are almost certainly big factors in his improved contact rate. Yes, there are still offensive issues for Adell: he’s swinging at balls far too often and even after a 66 point improvement in wRC+, his 95 mark is still below league average. From a StatCast perspective, his average exit velocity (85.9 mph) and HardHit% (29.7%) are both well-below league average, which is perplexing for a player with such clear power. So while his contact rate has improved a lot, the quality of said contact still leaves a lot to be desired.

But just because all of Jo Adell’s issues weren’t fixed in a year’s time doesn’t mean we can’t appreciate the meaningful progress he has made. Byron Buxton is the present example of this. He spent years making subtle improvements until all of a sudden he became one of the best players in the game this season. Adell is only 22 years old — making him almost a full year younger than our current top prospect, Adley Rutschman — and his demonstrated ability to change his swing and improve a major flaw leaves me optimistic that more positive adjustments are in store.

Luke Hooper is a designer and writer at FanGraphs. He lives in Portland, Oregon, longing for a major league team to materialize.

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I think it’s fair to worry if these changes are going to stick because swing tinkerers often go through periods where everything clicks and then periods where it doesn’t (Buxton is the most obvious example of this, but Jackie Bradley Jr and Jason Heyward also come to mind). And as it stands right now he’s not really someone you want to play every day in a corner outfield spot. He doesn’t get on base enough to compensate for the mid-range power, and he doesn’t hit for enough power to compensate for the fact that he only gets on base at a .300 clip.

Based on his past track record, I would think the most likely route for him being an everyday guy is if he keeps up the swing and taps into more of his power. In that case, you could see him as a viable major leaguer in the Adam Duvall mode. That seems a more likely direction than pushing his BABIP to stratospheric levels or improving the K/BB rate, although I suppose the latter is possible.