Breaking Down the Diamondbacks' 8 prospects in the Arizona Fall League

The Arizona Fall League released its 2025 rosters on Wednesday. The Fall League is a continuation league, played in six of the Spring Training Complexes in the Phoenix area.

Players chosen for the Arizona Fall League are usually those their teams need to decide on soon. They either missed development time during the season with injuries or are coming close to hitting Rule 5 eligibility.

The Arizona Diamondbacks' prospects will be playing for the Salt River Rafters, and playing in their home games in their own complex. They will share a team with their complex roommates, the Colorado Rockies, along with the Boston Red Sox, Pittsburgh Pirates, and Los Angeles Angels.

The fall league starts on October 6th, although Salt River's season starts the next day.

Here's a rundown on the seven players the D-backs are sending to the fall league, going from most to least major league ready.

RHP Drey Jameson

Jameson is the most important player on the roster to give reps to. He is the only one of the seven they're sending with a legitimate chance to make the Opening Day roster.

Following Tommy John surgery in September 2023, the team has converted him to a reliever for 2025. He appeared in three games for the D-backs, allowing two runs (one earned) in three innings. He's one of 16 pitchers to record a save for the club, having done so on April 20 in Chicago.

He's spent most of the year getting the feel back for his stuff with Triple-A Reno. Jameson has been out since May 20th with bone chips in his elbow, which led to him getting pulled from a rehab assignment in June. He's currently on Reno's 60-day injured list.

Jameson features the power arsenal that profiles for the back of the bullpen. He features a four-seamer, sinker, slider, changeup, and a sweeper. The first three pitches will be the most important for him to stick as a pitcher.

His four-seamer averages 98.3 MPH, but plays down due to a lack of rise (14.3" induced vertical break), low extension, and poor command. That's why he's developed a sinker as a better in-zone pitch. The sinker averages 96.5 MPH with 17.2" of arm-side run. The slider is the linchpin to his arsenal, as it's his primary chase and whiff pitch. In a short sample, he was producing a 50% whiff rate on the slider.

It's unclear if the team will stretch him out or have him pitch in short bursts instead for the fall league. The answer to that may determine the organization's plans for him in 2026.

RHP Kyle Amendt

If not for a shoulder injury, which wiped out three months, Amendt is probably pitching in the big league bullpen right now. The right-hander will appear in the fall league for the second year in a row.

The 6'5" right-hander uses deception and a high arm slot to attack hitters vertically. He tries to stay on the Zero Line (0" horizontal break) with his four-seamer (20" iVB), slider (0" iVB), and curveball (-10" iVB). While he doesn't offer premium velocity (low-90s fastball), the ability to throw three unique pitches with solid shapes gives him an edge.

With Reno this season, he pitched to a 3.75 ERA over 24 innings with a 31.7% strikeout rate and a 15.7% walk rate. He'll need to cut down on the walks to stick in a major league bullpen. He's gotten more chases, getting more swing-and-miss outside the strike zone. With his velocity, he'll need to work the lines of the zone to be effective.

For 2026, he should get a look at big league camp and should be on the list of midseason reinforcements for the bullpen.

RHP Yordin Chalas

Chalas spent the season on a starter's schedule as a means to accelerate his development. The idea was that he gets extra reps, as he'd pitch 3-4 innings once per week plus a bullpen session, as opposed to that same workload over multiple appearances.

He pitched as a glorified opener with High-A Hillsboro, trying to incorporate a four-seamer, slider, and splinker mix. He pitched to a 5.54 ERA in Hillsboro, but was a bit unlucky due to a 57.9% strand rate. He had a 21.4% strikeout rate compared to a 10.2% walk rate.

He missed one turn through the rotation with a minor injury, but otherwise has been healthy all season. Since getting promoted to Double-A Amarillo, he's worked strictly in relief due to a crowded rotation.

Chalas is more likely to end up as a reliever due to his high velocity and command issues. He profiles as a future back-end arm if he can develop any solid command with his fastball.

RHP David Hagaman

Hagaman is probably the biggest name from the D-backs prospect group. A strong run in the fall could push him towards Top 100 prospects status as early as next season.

One of three pitchers acquired from the Texas Rangers for Merrill Kelly, he's been the team's top performer down the stretch. He's pitched to a 3.15 ERA with a 35.5% strikeout rate and a 5.5% walk rate with Arizona's High-A affiliate in Hillsboro.

Hagaman slipped to the 4th round of the 2024 draft due to injury. He required an internal brace procedure, which ended his junior season at West Virginia. It also delayed his pro debut until June, but he's made up for lost time by being one of the more dominant arms in the lower minors.

Hagaman sits mid-90s with a fastball and complements it with a slider and a changeup. He has the stuff to be a mid-rotation starter; it's just a matter of getting reps. He's looking at a late 2027 debut, with a chance to earn a long-term spot in the D-backs rotation in 2028.

INF Jansel Luis

Luis is the best position player that the D-backs are sending to the fall league. He missed about three months with an injury in June, but has otherwise put together a solid season. With Hillsboro, he put up a respectable .304/.342/.422 slash (106 wRC+) with five homers and 22 steals.

Luis offers projectable upside as a switch-hitter. He's only 20, so he's yet to really tap into his raw power, which projects to be above-average. Ideally, as he climbs through the upper minors, he becomes more selective and unlocks more power.

The fall league is an opportunity to catch up on missed reps. He's likely ticketed for Double-A Amarillo next year. His double play partner, Cristofer Torin, was just recently promoted to that level this week.

For most of 2025, he played second base while Torin was at shortstop. That would seem like the possible development track, although he's behind Tommy Troy, who's knocking on the door for a big league call-up. The team has plenty of infield prospects and established veterans ahead of him, other than third base.

Luis is looking at a late-season call-up in 2027 at the earliest.

OF Jack Hurley

Hurley really struggled with Double-A Amarillo this season. The left-handed hitting outfielder slashed .224/.280/.368 (65 wRC+) with six homers for the Sod Poodles. That led to a one-month stint on the development list in June.

The most alarming part of his game was the massive jump in strikeout rate. While his swing-and-miss issues have been noted in the past, his swinging strike rate jumped above 22% and his strikeout rate over 40%. It goes without saying, but that needs to be cut significantly down if he wants to progress any further.

He's performed better since returning to Amarillo on July 29th, hitting .275 with two homers and an 88 wRC+. However, the strikeout rate is still above 40% over that stretch.

The hope is Hurley can reset and fix the holes in his swing in the fall league. He becomes Rule 5 eligible after next season, so time is running out. With the D-backs outfield situation completely falling apart in 2025, he has a chance to make a big league push next year with an improved approach.

C Kenny Castillo

Castillo is a glove-first catching prospect who hasn't exactly hit the cover off the ball in the lower minors. The 21-year-old slashed .218/.262/.342 with Hillsboro (64 wRC+).

Castillo missed the first month of the year with an injury. He appeared in 65 games with the Hops, although he was recently placed on the IL again.

The D-backs as an organization aren't particularly deep at the catcher position. Christian Cerda, Carlos Virahonda, and Ivan Luciano are the top prospects, but there's something left to be desired with the rest of them.

He becomes Rule 5 eligible in the offseason, but considering his track record, he's unlikely to be selected in either phase.

RHP Jacob Steinmetz

Steinmetz was the D-backs 3rd round pick in the 2021 draft, that includes Jordan Lawlar and Adrian Del Castillo.

It's been a slow climb for the 6'6" right-hander, as injuries have slowed his progress. 2025 was another such season, as he didn't appear in a single game with Hillsboro.

The right-hander features a four-seamer that hits mid-90s and a big downer curveball combination. With a lot of time missed due to injuries, it may be better for the D-backs to convert him to a reliever and fast-track his development toward the big leagues.