Arizona Fall League Prospect Stock Check-In

Here in Arizona we are now through two weeks of play in the Fall League, with some schedule alterations (a few days of cancellation and a doubleheader makeup effort Tuesday) caused by the impact of tropical moisture coming up through Mexico’s Pacific Coast. Though roughly 60% of the slate remains, there are already some individual players who have moved the scouting needle either for me, or for the many folks here braving Bell Road and walk-prone pitching to sharpen their club’s understanding of these guys. I’ve pushed a bunch of updates to the 2025 Fall League tab on The Board, and below have a Map Key so you can quickly parse the basics of those updates, as well some scouting notes on the players whose grade or projection has changed.

Trend Column Map Key
You’ll notice the “Trend” column on The Board. There are several (mostly self-explanatory) symbols there to give you an idea as to the way a player has looked. The “Up” arrow indicates someone has played well enough, or looks different enough, for me to have upped their FV grade from prior reporting. It’s possible the upward trend will continue throughout the Fall and that the player’s grade increases yet again during offseason org list work. In the cases where the player is struggling so badly as to have earned a “Down” arrow, I haven’t nerfed their FV grade at this time because, historically, there are lots of great players who struggled in the AFL because of fatigue, indifference, or some other reason independent of their talent.

The target “🎯” signifies either players whom I haven’t seen yet, or players who might be Up arrow guys if they reinforce a good early look with more of the same. At a certain point (like a weekish from now) the games I decide to attend on a given day will be dictated entirely by who is left on my target list. The “New” tag indicates players who weren’t on The Board previously, and the Band-Aid “🩹” designation indicates either players whom I haven’t seen, or those who aren’t playing due to injury.

New Faces
Esmerlyn Valdez, OF, Pittsburgh Pirates
Owen Ayers, C, Chicago Cubs
Hudson Leach, RHP, Houston Astros

Valdez had a stellar 40-man platform year (.286/.376/.520 with 26 home runs) in a 2025 season split between High- and Double-A. He’s gone nuclear here in the Fall League and hit his eighth homer yesterday in his ninth game. The big piece of Valdez’s 2025 was the dip in his strikeout rate. He went from punching out 30% of the time in 2024 to just 24% of the time this year. The improvement coincided with a mechanical change (his hands set up more vertically than in 2024) so there’s at least some visual evidence that Valdez has actually changed, though he still swings underneath a ton of fastballs. There’s more in his updated report on The Board, but in short, he looks a lot like Randal Grichuk (pull-heavy righty corner outfield cog) and should be contributing to Pittsburgh’s outfield mix by late in 2026.

Pirates prospect Esmerlyn Valdez hit 26 homers in 123 games this season.

And he brought the power to the AFL ?

Check out his homer from his fall league debut ?? pic.twitter.com/mLEXmtokqG

— Baseball America (@BaseballAmerica) October 8, 2025

Ayers has an incredible arm, he has the lightning-fast exchange of an undefeated late-1800s gunslinger, and has routinely popped sub-1.9 for me this Fall with throws right on the bag. The other aspects of his catching defense are not great, but Ayers is a recent small-school draftee ($50k out of Marshall in 2024) and deserves time to develop back there. Can he hit? He performed as an old-for-the-level hitter at Low-A in 2025 (Ayers is 24) and has looked good against mostly bad pitching in Arizona, with roughly average raw power but vulnerability to elevated velocity. He’s definitely on the prospect radar now, but his role and projection are still pretty fuzzy and dependent on him improving as a receiver.

Hudson Leach is a potential power reliever who has the best pure breaking ball I’ve seen so far this Fall. Check out his fresh report on The Board for more.

In the Mix as Major League Starters
Luke Sinnard, RHP, Atlanta Braves
Spencer Miles, RHP, San Francisco Giants
Anderson Brito, RHP, Houston Astros

One of the interesting thought exercises while scouting the entire Fall League is, “Which of these guys can be major league starters?” There are some years where there are several good guys, and some with only one or two. This year’s contingent had several candidates from the jump (like Luis De León, Jake Bennett, Jose Corniell, and Hagen Smith, all of whom I think you can make a coherent argument belong on this offseason’s Top 100 list) and a handful more are emerging, including the names above.

The 6-foot-8 Sinnard only began playing baseball during his senior year of high school. He started his college career at Western Kentucky, then had a sophomore breakout at Indiana when he set the school’s single-season strikeout record with 114 in 86 1/3 innings. He blew out during his Regional start at the end of 2023, had Tommy John, and was back in time to throw some scouted pre-draft bullpens in 2024, including at the Combine. Sinnard looked good enough in those settings for the Braves to use a third rounder on him, then he saw his first pro action in 2025 and worked an efficient 72 innings split between Low- and High-A. He missed roughly six weeks in June and July recovering from an elbow stress reaction, which is why he’s in the Fall League picking up innings. He’s added a splitter that wasn’t there in college, he can mix breaking ball shapes from cutters to curveballs, and he’s commanding a 92-96 mph fastball with uncommon precision for a guy his size.

Miles and Brito have more relief risk. Miles is built like a starter at a strapping 6-foot-3, and has a starter’s four-pitch mix, but he’s barely pitched since turning pro in 2022 due to multiple injuries, and he has basically zero innings foundation. He’s Rule 5 eligible this offseason and is pretty likely to end up in a bullpen if he’s rostered this offseason. If the Giants don’t roster him and nobody drafts him in December, his chances of starting (thanks to another year with purely developmental focus in 2026) improve.

Little Astros righty Anderson Brito (whom I’ve seen once bad and once very good) is only 5-foot-10, 160 pounds or so. There are many more relievers who look like him, physically and mechanically, than there are starters. But Brito has one hell of a curveball, throws really hard for a 5-foot-10 guy, and still has multiple years to develop as a starter because he isn’t Rule 5 eligible until 2027. If you want active precedent for a guy this little succeeding as a starter, Sonny Gray provides some amount of it, but he’s maybe the only one from the last decade or so to have a prolonged career as a starter at 5-foot-10. For every Sonny Gray there are many more David Robertsons (if Brito were to become a career-long setup man like Robertson, that’d be a great outcome) and Deivi Garcias. I think it merits developing Brito as a starter just to see what happens, but he’s the one of this group I’m least convinced will stick in that role.

Rebounding After Uneven Seasons
Seaver King, SS, Washington Nationals
Jared Thomas, OF, Colorado Rockies

King, the 10th pick in the 2024 draft, posted a .244/.294/.337 line combined at High- and Double-A in 2025, good for only an 87 wRC+. Scouts think his swing still needs polish to truly take full advantage of his athleticism, but King has looked awesome on both sides of the ball out here, and has made it easier to dismiss his 2025 mediocrity as anomalistic. Jared Thomas’ strikeout rate ballooned to over 30% after he was promoted to Double-A Hartford during the second half of 2025. His hands are so alive with power for a fairly skinny, projectable, left-handed hitter that, at least during my in-person looks, I have more excitement than concern about the makeup of his offensive skillset. Both of these guys are sensational athletes who are still just 22 years old, in stages of both physical and technical development that invite projection more than they do trepidation.