Taking a Look at Six Fall League Prospects on the Rise

A lot of different types of players get sent to the Arizona Fall League by their parent clubs: prospects who have lost time due to injury, org arms there to soak up enough innings for the league to function, guys eligible for the Rule 5 Draft whose teams aren’t yet sold on putting them on the 40-man roster, and, quite often, the most talented and exciting players in minor league baseball. It’s a rich and robust tapestry.

Now that the league’s action has commenced, one use of the AFL is to provide a sort of decontextualized look at some of the players whose strong performance in 2025 was already cause for some re-evaluation. Here’s one player from each AFL roster who arrived with some helium, prompting us to ask if they’ve changed their scouting report, or are just progressively improving into the player we expected.

Glendale Desert Dogs
Sam Antonacci, 2B, White Sox
2025 FV: Honorable Mention

Not only did the White Sox trade for Chase Meidroth months after giving Antonacci a slightly over-slot bonus in the fifth round of the 2024 draft, their Double-A Birmingham affiliate won the Southern League while slotting Antonacci in as the third straight feisty little bat-to-ball maven at the top of their lineup behind Rikuu Nishida and William Bergolla. At six feet, he’s a bit taller, but similar to Meidroth, below-average thump and a dearth of the athleticism necessary to drive a shortstop projection cooled early scouting reads for Antonacci, and he was an honorable mention for us on the White Sox list in April. Despite only playing his junior season there after two years of Division II ball, Antonacci is so Coastal Carolina-pilled that 35 hit by pitches form a substantial part of the .433 OBP he held over his first full pro season. (That he has yet to be plunked in his first three AFL games has to be, one would imagine, a source of deep personal disappointment.)

Antonacci’s swing is unsurprisingly compact and wristy, using a small leg kick from a slightly open position just to load into his backside, as he’s more interested in freeing up his hands to manipulate the barrel around the zone than he is in creating separation. He’s compactly built without much projection to improve his below-average raw power, but he’s also the type of hitter to choke up on the bat even when he’s ahead in the count in a spot where a single scores a run. He’s capable of some jailbreak sprints a shade under 4.2 seconds out of the left-handed batter’s box, but he stole 48 bags with largely average run times. Maintaining third base versatility is important for his profile, but Antonacci’s arm is stretched there and it shows up in the form of rushed actions, though his range is also below-average at the keystone.

His contact rates are good, but he’s a little too vulnerable to velocity up and away to project Antonacci to be a 90% or better in-zone contact specialist. He chased around 20% at Birmingham, but will need to maintain his Caleb Durbin-levels of plunking absorbance to live as an OBP machine with limited defensive value. Antonacci already has a reputation for the kind of relentless motor that minor league skippers love, and that will be needed for him to transcend a bench role. A groundball that doinked off the second base bag and into right field during the Southern League playoffs, resulting in a throwing error prompted by Antonacci’s hustle double attempt, is kind of his game in a nutshell.

Verdict: He’s performed so well that he almost has to be a 40, but his tools are too limited to push him further until he performs some more.

Mesa Solar Sox
Bryce Cunningham, SP, Yankees
2025 FV: 40+

Cunningham sprinkled in two star turns on the Cape between his three seasons at Vanderbilt, then was popped by the Yankees for around $2.3 million in the second round of last summer’s draft, so a trip to the AFL doesn’t necessarily constitute a new level of scouting exposure for the 22-year-old right-hander. But between not pitching after the draft last year and missing over two months this summer with shoulder inflammation – necessitating the Fall League innings – Cunningham is a bit more of an unknown commodity than his origins would suggest.

Two months into 2025, Cunningham was working 92-96 with big time extension and pitching his way into Top 100 consideration. He ran a 1.93 ERA in Hudson Valley through 46 2/3 innings, striking out 25.7% of High-A hitters with just a 6% walk rate before going on the IL in early June. His velocity was roughly similar, but his delivery less consistent, upon returning for four abbreviated and disjointed outings, and he struggled with his secondary command while getting dinged for four runs in his two-inning AFL debut. Cunningham throws from a three-quarters slot but is so massive (6-foot-5, 230 pounds) that his release height is still roughly six feet, adding some downhill plane to a fastball that was homer prone at Vandy. But the pitch has good shape with nearly 18 inches of induced vertical break, it missed bats at an above-average rate in High-A, and he’s shown some ability to command it at the top of the zone. His high-spin changeup is unique but monstrous, racking up a 48% miss rate this year.

Cunningham was a 40+ FV in January, largely due to some wobbling in his strike-throwing and the need for a new breaking ball. Characteristically, the Yankees have had Cunningham work on a sweeper that has produced solid results. But as someone who already had rotationality in his delivery, opening his front toe slightly to the first base side, it bears monitoring how Cunningham’s newer breaking ball performs alongside his efforts to regain his early-season command. His first outing for Mesa also found him sprinkling in a developing curve.

Cunningham is still tracking well as a no. 4 starter long-term, but you can dream on more if his first-half form pops up in the desert.

Verdict: There’s potential for a grade jump here soon, but Cunningham’s post-injury form didn’t look quite ready to secure it and he was roughed up in his AFL debut.

Peoria Javelinas
Luis De León, SP, Orioles
2025 FV: 45

Loose and projectable with bat-missing secondaries, De León entered 2025 within range of pitching his way into 50 FV consideration by season’s end, but his start was delayed until May by a right elbow impingement. He returned sitting about 94 mph and showed sufficiently improved strike-throwing to earn a three-outing cameo in Double-A, where he carved up Eastern League hitters to the tune of a 1.69 ERA and 35.3% strikeout rate in 16 innings. He isn’t Rule 5 eligible until next winter, but the AFL offers him the chance to build upon the roughly 87 innings he’s now thrown in back-to-back seasons. He was stretched out to four innings in his debut for Peoria on Wednesday and looked fantastic, striking out seven and walking two behind wipeout secondaries.

De León’s whippiness is really evident when you watch him plant his front foot and explosively rotate around it. It adds nasty lefty crossfire action to his slider and changeup, which each ran miss rates in the mid-40s all year, with his command of the latter still standing apart from the rest of his arsenal. His arm action is still long, but added strength has brought more stability to De León’s delivery, which is visible in both his upper and lower halves. Relatedly, the 10.9% walk rate he held across three levels this year was a career best. His sinker has heavy running action, matching the rest of his east-west arsenal, and he can find himself spraying it wide when his arm is late at foot strike, but it certainly keeps the ball out of the air. De León has allowed just five home runs in 256 2/3 pro innings and has yet to add any to his tally this season.

Theoretically, this affords LDL all the tools required to dodge the worst aspects of the charnel house that is pitching in Arizona. More performances like Wednesday’s, and more flashes of the 95-97 mph range he’s shown at times, would really tie together a case for inclusion in the Top 100. But the continued plus performance of all three parts of De León’s arsenal, along with some more palatable walk rates, has already earned him a backend starter projection.

Verdict: I think LDL might be a 50, but I have to go in back and ask my manager first.

Salt River Rafters
Esmerlyn Valdez, OF/1B, Pirates
2025 FV: Honorable Mention

The hulking Dominican slugger, listed at a wildly implausible 6-foot-2, 181 pounds, was an honorable mention on our Pirates list in the spring due to hit tool concerns and a first base projection. A 26-homer campaign in 2025 (with the final six hit in Double-A), along with a six percentage points reduction in his strikeout rate (24.6%), would have forced us to give Valdez more acknowledgement even before he whacked two tape-measure shots in his opening week with Salt River. A combined .286/.376/.520 line as a 21-year-old simply deserves more regard, even if that comes with more hit tool scrutiny. Valdez switched from a big leg kick to a more moldable toe tap as part of a larger injection of rhythm into his operation, which has him syncing up his first move with the pitcher earlier in the process, and he’s seen incremental gains in his swing decisions, nudging his contact rate over 70% along with it.

But Valdez still loads his hands late, a last little gathering move at the end of a full-body effort to swing very hard. Accordingly, he is very vulnerable in the upper third of the zone, especially against velocity. So while there’s the potential for 70-grade raw pop here with real feel for pulling and lifting hard contact, especially when he can catch secondaries out front like the hanger he whacked 114.4 mph the other day, there’s still a pretty clear book on how upper level pitching will neutralize Valdez’s power. Defensively, Valdez spent more time in the outfield this year than last, but he’s still too raw in his route-running and struggles too much with the footwork necessary for making accurate throws to project him to stick out there.

That puts a number of big hurdles between Valdez’s massive juice and a path to being a regular, or even just the decision to protect him from the Rule 5 Draft; his burly start to the AFL is coming on the eve of the Pirates having to make a 40-man roster decision. We see Valdez tracking more like a slow-burn bench bat with lots of whiffs, like a right-handed Daryle Ward, but that’s already a meaningful step up from this time last year.

Verdict: You hit 26 homers — er, 28 now — as a 21-year-old, you get added to The Board, even if you can’t play much defense.

Scottsdale Scorpions
Ethan Petry, OF, Nationals
2025 FV: 40

Focusing on two hulking right-handed sluggers with hit tool limitations and first base projections wasn’t the original design, but in a world where Nacho Alvarez Jr. is playing in the AFL despite having over 200 major league plate appearances to his name, Petry making the same trip in his draft year was too interesting to overlook. The Nats popped Petry for just over $2 million in the second round, but he received barely the fourth-largest bonus Washington issued as they spread around the wealth of a well-under-slot deal with first overall pick Eli Willits. There’s a certain logic to juicing the pace with Petry, a physically mature slugger who hit 54 home runs in three years at South Carolina but missed the final weeks of his junior season with a shoulder injury.

But a sub-70% contact rate suggests that even the collection of upper level org arms scattered across the AFL could offer a substantial learning curve for Petry, and the first couple days have looked appropriately rough. Often hitters will adopt a toe tap as a shorter alternative to a leg kick, but that Petry uses the former to load up a smaller version of the latter reflects the length in his operation. For all of his length and difficulty tracking spin in his pro debut, his strikeout rate didn’t immediately explode (24.5%) in the Carolina League, and he flashed a more contact-heavy approach in his final season at South Carolina before the injury. The holes in Petry’s hit tool loom larger because at his tremendous size (6-foot-4, 235 pounds) and related lack of speed, staving off a move to first base will be an uphill climb (he’s expected to play some first in the AFL).

Petry has 70-grade raw juice and a history of actualizing a good chunk of it, with the sort of strong build that suggests a transition to a more compact and stabilized loading action is possible. It’s not like there isn’t a path to impact here, but his median outcome is still trending toward bench bat.

Verdict: It’s a volatile 40 FV because of how early it is in his pro ball journey, but Petry still looks like a 40, at least at this stage.

Surprise Saguaros
Marco Dinges, C/DH, Brewers
2025 FV: 40

I was supposed to write up Dinges in May and cried uncle after a few days of watching him, unable to figure out what to do with this hyper-twitchy bat speed merchant who rarely pulls fastballs, this athletic but undersized college catcher who had barely caught. Dinges has long-term hit tool concerns, but was also posting Mitch Jebb-level strikeout rates in the Carolina League. His rotational explosiveness offers enticing raw pop, but he also maintains a fairly level swing plane. Contradictions like this abound for Dinges.

Eric shook it out to a 40 FV backup catcher grade, with simultaneously more risk and more ceiling than that label typically portends because Dinges might hit a fair deal more than such a label suggests and also may not catch at all. Shortly after the Brewers list was published, Dinges got a promotion to High-A, which brought performance feedback more formed to his skill set. He still hit an impressive .273/.371/.483 in 51 games in the Midwest League, but his contact rate slid below 70% as the anticipated in-zone whiff issues came home to roost, albeit over the same timeframe that saw him swat 10 homers.

In the middle of this was a left hamstring strain that knocked Dinges out for over a month, limited him to 47 games caught on the season and made an epilogue in the AFL seem appealing. His first week back from injury contained the worst of his whiff issues. Dinges uses his bat speed as an opportunity to stay closed deep into his load, before swinging open like an unlatched gate in a gale. Not coincidentally, he produces good swing decisions for an offensive profile that is heavier on athleticism than feel to hit, bristling with bat speed more than it is optimized for power production. It’ll be easier to wait for Dinges’ offensive tools to win the day if his catching development buys time.

To that end, Dinges is agile enough and has the raw arm strength to produce plus pop times, but the consistency of his footwork is raw, and his narrow base serves to make his glove movements a little jerky for framing and gives him a small target window for keeping blocked balls in front of him. The main items of need here are reps and added bulk, and outdoor baseball in Arizona is only good for one of those.

Verdict: If you read the text above and think I know what to say about Dinges, I don’t know what to say to you either. But he bears watching.