Jo Adell Remains a Work in Progress — But He’s Making Progress

If you were only going by raw stat lines, the end of April would have been an understandable time to give up on Jo Adell. After struggling mightily in parts of four seasons with the Angels as well as the first half of 2024, he showed some positive gains in the second half before being shut down due to an oblique strain in early September. He finished in replacement-level territory, with a 90 wRC+ and 0.1 WAR, then was dreadful at the start of this season, sticking out even among one of the majors’ worst offenses. Lately, though, Adell has come around in promising fashion, offering hope that he can be a productive big leaguer after all, if not the star so many once believed he could be.

Originally, I intended to use the 26-year-old Adell to lead off the 2025 version of an article I wrote last year, covering players who had improved the most after dismal starts — even if their overall numbers were camouflaged by their early struggles and still came off as rather ordinary. Using May 1 as a cutoff, with a minimum of 80 plate appearances on either side, I found that Adell had improved the most from the first leg of the season to the second. Here’s the table, with the stats updated through Sunday:

Adell hit just .190/.236/.310 with two home runs in March and April while striking out 27% of the time, but from the start of May through Sunday, he hit .255/.344/.582 with 11 homers while trimming that strikeout rate to 23.2%. He was about half a win below replacement level before May 1, and has been about a full win above since.

I’ll dig into the numbers below, but first, a recap. A 2017 first-round pick out of a Louisville high school, Adell cracked our Top 100 Prospects list in each of the next three seasons, ranking as high as no. 4 in 2020, as a 65-FV prospect, and he was similarly regarded by other outlets thanks to his combination of plus-plus raw power and plus speed. But since debuting early in the 2020 season, he has generally struggled to make good contact, or any contact at all for that matter, with his lack of refinement limiting his opportunity to show off the tools that so tantalized talent evaluators. In a total of 178 major league games from 2020–23, he hit just .214/.259/.366 with 18 homers in 619 plate appearances en route to a grim 70 wRC+. After appearing in 88 games with the Angels but managing just a 77 wRC+ and -0.2 WAR in 2022, he played only 17 games in the majors in ’23 while returning to Triple-A Salt Lake for the fourth year out of five. As I joked early last year, when it looked like he might be breaking out — which proved not to be the case, alas — if he’d spent just a bit more time in my hometown, my parents would have been obligated to invite him over for dinner.

Indeed, contrary to the title of that check-in (“Jo Adell Is Finally Putting It Together”), Adell did not put it together, but because he was out of minor league options and the Angels were out of better ideas, he remained in the lineup. He basically had one excellent month in the first half of the season (March/April, 171 wRC+), one in the second half (August, 128 wRC+), and a decent one in the middle (July, 104 wRC+), but the rest was pretty cringeworthy. Still, when broken down by halves, one could see some progress:

Adell’s strikeout and walk rates both improved, but his contact was a mixed bag. His expected batting average jumped from .217 to .238 in the second half, while his expected slugging percentage fell from .432 to .392, to the point that the two developments nearly cancelled each other out; his xwOBA barely inched upward, from .309 to .318.

There was more going on during that second half than those stat lines suggest. At the end of July, after experimenting with hitting coaches Johnny Washington and Tim Laker first in spring training and then more recently in pregame work, Adell ditched a leg kick that he had used for his entire career. “Adell had always brought his front foot about 12 inches off the ground as he prepared to swing, using that trigger mechanism on all pitches,” wrote the Orange County Register’s Jeff Fletcher. “On Tuesday [July 30], though, Adell simply lifted his heel, keeping his toe on the ground.”

Here’s a home run Adell hit off the Tigers’ Shelby Miller on June 30, 2024, with the kick still in place:

And here’s the one he hit off the Rockies’ Jake Bird on July 30, in his first game without the kick:

Here’s another one without a kick from August 31, off the Mariners’ Bryan Woo:

I presented that last one to help illustrate how Adell gradually opened up his stance. We don’t have granular game-by-game data, but from Opening Day through the end of June, Adell’s stance was closed by two or three degrees according to Statcast’s monthly averages. In July, however, his stance was open by an average of three degrees; that increased to 10 degrees in August, and in his five September games (during which he went 1-for-14 before getting injured), he was open by 11 degrees.

During spring training, Adell experimented with bringing back his leg kick, believing he could use it, at least on a situational basis, to take advantage of his natural athleticism. He hit a grand slam off the Dodgers’ Dustin May using the leg kick on February 28, but as far as I can tell, he didn’t bring his leg kick back into regular-season games until May 26, by which point he’d already turned the corner after his terrible opening stretch. From that point he went on a binge, hitting .328/.409/.724 with seven home runs from May 26 through June 15 against the Yankees, Guardians, Red Sox, Mariners, A’s, and Orioles. Variants of the kick, which to these eyes appear less pronounced than last year, show up in all four homers he hit against the Mariners and A’s from June 7–11:

Adell’s stance was open by an average of 12 degrees in March and April, but he’s back to 10 degrees since. His swing path tilt has been consistent at 32 degrees from month to month, one less than last year. Likewise, his average attack angle — the vertical angle at which his bat is traveling at the point of impact, has remained consistent at eight degrees, where it was generally at five degrees last year, through good months and bad. It’s an uppercut, but hardly an extreme one.

Regardless of the angles, the one constant is Adell swings hard. His 77.3-mph average bat speed ranks fourth among qualifiers, behind only Oneil Cruz, Junior Caminero, and Jordan Walker, while his fast swing rate of 69.7% ranks fifth. His 26.8% squared-up rate is way down in the seventh percentile, but his 14.3% blast rate is up in the 81st.

Long story short, Adell is hitting the ball harder than last year, and thanks to that improved strikeout rate, he’s making contact more often:

When he does connect, Adell manages to find the barrel with some frequency; last year’s rate placed in the 79th percentile, this year’s in the 86th. Beyond that, his expected stats have improved dramatically from year to year, by 49 points of batting average and 130 points of slugging percentage, but so far, his actual numbers have improved by less than half those margins. Still, that’s progress. His contact actually wasn’t that bad in March and April; he was 62 points short of his xBA and 116 points short of his xSLG during what otherwise looked like a miserable month. Even since May 1, he hasn’t gotten the results his quality of contact suggests. But between that and his improved strikeout and walk rates, he’s in uncharted territory, xwOBA-wise:

It’s particularly encouraging to consider what Adell has done since last July 30, when he first ditched the leg kick; across that span of 411 plate appearances, he’s hit .230/.309/.439 with 20 homers, a 12.5% barrel rate, 25.3% strikeout rate, and a 111 wRC+. That’s not star-caliber, but it’s certainly playable for a center fielder (more on that subject below) despite his struggles last September and early this year.

What does concern me is Adell’s pitch splits. This year, he’s absolutely feasted on sliders, and to a lesser extent sinkers, which together account for about one-third of his pitches faced:

Adell was four runs above average against sliders last year and is already eight above average against them this year, which puts him in a virtual tie with Fernando Tatis Jr. and Jacob Wilson for the major league lead. He’s been about average against sinkers, but against four-seamers, he’s still struggling terribly. You have to go back to 2021 to find a season in which he managed a batting average above .181 or a slugging percentage above .375 against four-seamers; he hit .261 and slugged .500 against them in 50 PA that year. He was eight runs below average against four-seamers last year, and is two below average this year, though at least his expected numbers against them are good, and he has more areas in the strike zone where he’s not a total pushover:

That said, if we again split Adell’s season using May 1 as the dividing line, a trend toward improvement becomes clear:

In table form:

That comparison is night and day, even if he’s been falling short of his expected numbers over both stretches. Adell still has some major holes in his swing, but he can be a productive major leaguer if he continues to handle the heat as he has over this recent stretch.

As for Adell’s defense, last year he proved to be a capable right fielder, with 6 DRS and -2 FRV in 1,035 2/3 innings. With the Angels making the long-overdue decision to shift Mike Trout to right, Adell has been pushed to center, where he played just 34 innings last year and just 122 in his previous major league career. The small-sample data suggest he’s stretched: In 42 games (41 starts) totaling 355 1/3 innings, he has -6 DRS and -4 FRV, compared to -1 DRS and 0 FRV in 155 innings in right during Trout’s absence due to a bone bruise in his left knee. It probably hasn’t helped that his main right field neighbors Trout (-3 DRS and -2 FRV in 185 innings) and Jorge Soler (-2 DRS and -3 FRV in 217 innings) — the latter of whom has more or less taken over the position while Trout has been limited to DH duty since his return on May 30 — have been subpar. Soler has had multiple seasons with double-digit negative runs by one metric or another in right, including -10 DRS and -7 FRV in just 326 innings there last year. That’s worth keeping in mind when considering Adell’s metrics in center.

When I wrote about Adell on May 13 of last year, I was somewhat optimistic he’d turned a corner, though I did conclude that he remains a work in progress. I’ll say the same thing this year, albeit in a more measured tone. He’s giving off some encouraging signs, and one can’t fault the Angels’ patience with him or his willingness to experiment. I don’t think Adell will ever reach the ceiling that talent evaluators expected from him, but I do think he can be a productive major leaguer, and after all of the struggles we’ve seen from him, that counts for something.