10 Notable Pitchers Who Threw In Arizona Instructional League

Just because some players didnâ€t make their pro debut this season doesnâ€t mean they werenâ€t putting in meaningful work behind the scenes.

The instructional league provides a key developmental setting, giving prospects a chance to log extra reps—often against players whoâ€ve already competed in affiliated ball. While the games are more controlled and focused on development, the environment still pushes players to refine their tools and adjust to the demands of pro ball.

For pitchers in particular, the instructional period is crucial. Many recent draftees follow structured throwing programs to gradually build arm strength and recover from the workload of the spring. In many cases, that means ramping up before returning to consistent work off the mound, making this window a vital stepping stone in their progression.

Here are 10 interesting pitchers who threw in instructional league in Arizona.

Yujanyer Herrera, RHP, Rockies

Herrera entered the year ranked No. 13 in the Rockies†system, but missed the entire season recovering from Tommy John surgery, and the Rockies also added several arms at the trade deadline, so he fell off the list. Still, thereâ€s plenty of optimism within the organization about the Venezuelan righthanderâ€s long-term potential.

Herrera has clean mechanics, a projectable frame and an advanced feel for pitching. The 22-year-old has returned to the mound, showing encouraging signs of progress. His fastball and sinker are both sitting comfortably at 94-96 mph, and heâ€s been steadily building up his workload, often working multiple innings per outing as he regains his pre-injury form. Herrera primarily leans on a fastball-slider combo, but he also mixes in a curveball and changeup, giving him a four-pitch arsenal with starter upside. He was acquired alongside Bradley Blalock in the 2024 trade that sent Nick Mears to Milwaukee.

Antoine Jean, LHP, Rockies

Jean struck out 110 batters on his way to earning Big 12 Pitcher of the Year honors at Houston, showcasing dominant stuff and mound presence. However, his draft stock took a hit due to two key factors: his age—he was the second-oldest player in the MLB Draft—and Tommy John surgery that knocked him out of the 2023 college season. Despite those concerns, the Rockies saw enough potential to select the 24-year-old in the seventh round, and heâ€s already flashed glimpses of the form that made him so effective in college.

Jean features a distinctive over-the-top release, which adds natural deception to his delivery. His 93 mph four-seam fastball travels on a clean, direct line, but it stays hidden unusually well until the last moment, giving it some sneaky life. That same arm action sets up his curveball effectively. It’s a classic 12–6 breaker in the upper 70s that tunnels well off the fastball.

Riley Kelly, RHP, Rockies

Kelly was a driving force behind UC Irvine’s 2025 success as its rotation anchor and workhorse. The Rockies eased their 2025 fourth-rounder into pro ball by pitching in instructs rather than assigning him to an affiliate. There, the 21-year-old made a handful of multi-inning starts, offering a glimpse of the same traits that defined his college profile. He leaned heavily on his fastball, which sat in the 93–94 mph range, though early outings were marked by some command inconsistencies. Still, the Rockies are optimistic that with continued development and a full offseason, Kelly can build on his foundation and compete for a rotation spot at the lower levels in 2026. Kelly’s fastball is already fairly deceptive, so he could take a step forward in 2026 if he can find a way to add a bit more velocity.

Michael Lombardi, RHP, Royals

Lombardi, the Royals’ highest-drafted pitcher in 2025 as a second-rounder, boosted his stock in the spring at Tulane with a well-timed uptick in velocity. In instructs, Lombardi’s fastball sat around 95 mph with solid command, mostly in two-inning outings. While his fastball impressed, scouts were more mixed on his secondary offerings, especially because of inconsistent offspeed command. However, thereâ€s a strong consensus that his sharp, 12–6 curveball has the potential to develop into a devastating putaway pitch. With continued refinement, Lombardi has the tools to emerge as a high-upside arm in the Royals†system.

Shotaro Morii, RHP, Athletics

The A’s have increasingly tapped the Asian international pitching market in recent years, adding prospects like Wei-En Lin and Chen Zhuang to their Top 30 Prospects. Morii is one of their most notable recent additions. The two-way player signed this past year for $1.51 million, the largest bonus ever given to a Japanese amateur outside of Nippon Professional Baseball.

Morii debuted as a shortstop in the Arizona Complex League, showing a solid all-around game at the plate and in the field. The righthander, who had been up to 95 mph as an amateur took the mound for the first time during instructs and his fastball sat 89-91 mph. He also flashed a sharp slider and a fading splitter, both of which induced swings and misses and hinted at real upside on the mound. Morii, who turns 19 in December, could begin 2026 in the ACL as a pitcher before advancing to Low-A.

Josh Owens, RHP, Rangers

If there were a standout award for Arizona instructs, Owens would be firmly in the mix. The Rangers†third-round pick in 2025 impressed with both his bat and arm, turning heads as a potential two-way talent. On the mound, the 18-year-old showed a deceptive sidearm delivery and a 92-93 mph fastball, hinting at a profile built more around movement and deception compared to pure velocity. He also features a developing slider and changeup.

Some scouts believe Owens has a real shot to stick as a true two-way prospect. He got an early taste of that challenge following a promotion to Low-A Hickory, where he pitched four innings across two starts and appeared in eight games as a position player. Though still raw, his poise and performance on both sides of the ball have made him one of the more intriguing young names in the Rangers†system.

Kruz Schoolcraft, LHP, Padres

Schoolcraft has already taken rapid strides between his high school senior spring to now. The 6-foot-8 lefthander now looks more physical, more refined and flashed some electric stuff. His fastball sat comfortably at 97–99 mph with late life, and he complemented it with a firm changeup that touched 90. He didn’t throw a slider against a righty-heavy lineup in the game Baseball America observed, but amateur scouts believed it had above-average potential with plus reps. With his towering frame, fast arm and high-octane arsenal, Schoolcraft fits the mold of a frontline-caliber pitching prospect. Some scouts have even drawn early comparisons to a young A.J. Puk.

AJ Russell, RHP, Rangers

Russell took an intriguing path to pro ball. He dominated for Tennessee as a full-time reliever in 2023, then jumped into the rotation in 2024 until UCL surgery cut his season short and sidelined him for most of the 2025 season as well. Still, he flashed enough in the SEC for the Rangers take a calculated gamble on him in the second round this year. Scouts who saw him in instructs understand the appeal.

The righthander works from a low three-quarters arm slot and consistently fills up the zone with a 92-94 mph fastball. Some even believed it was one of the best fastballs in the 2025 class when he’s healthy. His ability to create natural movement from his slot gives him a foundation that could play in multiple roles moving forward, but his lower arm angle also contributes to spotty control at times. While a small sample size in instructs, Scouts who saw Russell pitch as an amateur believe his slider has improved since then. He also throws a low-80s changeup. To truly take a step, he’ll need to hone in on more development of his secondaries.

Zane Taylor, RHP, Athletics

Taylor didn’t spend much time in instructs, because the A’s saw enough in their 2025 fifth-rounder to send him to Triple-A Las Vegas for his pro debut, where he impressed with two scoreless innings and four strikeouts. The UNC Wilmington product remained with the Aviators through their run to the Triple-A National Championship, though he didnâ€t appear in the game. Taylor was a dominant force in college, earning Colonial Athletic Association Pitcher of the Year honors and leading all NCAA Division I pitchers with an exceptional 9.6 strikeout-to-walk ratio. Equipped with a slider and a changeup, Taylor saw his stock rise by adding an extra zip in velocity to his 93-95 mph fastball.

JD Thompson, LHP, Brewers

Thompson was a tone-setter for Vanderbilt from his very first start of the year when he struck out six Grand Canyon batters over 4.2 innings in Arizona. That early outing laid the groundwork for a strong spring that ultimately boosted his draft stock. Fittingly, the Brewers†second-round pick is now beginning his pro career just four miles from where his college season started. Much has changed in a few short months, but for the 22-year-old lefty, many of the same tools remain on display. He consistently commanded his 93-95 mph fastball, and his snap-style release gives both his slider and curveball a deceptive look out of the hand. 

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