#16 - RHP Luis Gastelum
Scouting grades: Fastball: 45 | Changeup: 70 | Slider: 45 | Command: 55 | Overall: 40+
Background:
Luis Gastelum was signed by the Cardinals as a minor league free agent out of Mexico in 2023. He pitched in the Mexican Pacific Winter League prior to signing, but there wasn’t much buzz about him heading into 2024. That changed (no pun intended) quickly. Gastelum burst onto the scene with a breakout campaign and forced his way onto the prospect radar with arguably the best individual pitch in the system—his Bugs Bunny changeup. Despite being an older international signee, he has quickly emerged as one of the most intriguing relief arms in the organization—thanks in large part to what might be the best changeup in all of minor league baseball.
Scouting Report:
Gastelum doesn’t possess a traditional power bullpen arsenal, but his changeup is a legitimate outlier—both in terms of movement profile and effectiveness. The pitch features an absurd -2 inches of induced vertical break and 15.4 inches of arm-side run, tumbling to his arm-side with heavy drop and run. What makes it even more remarkable is how well Gastelum commands it. He throws the pitch nearly 50% of the time—and consistently locates it effectively, landing it for strikes or burying it just off the edge to induce chase.
Even more impressive than the pure movement profile is how well the pitch played in the Florida State League. Gastelum’s changeup doesn’t just flash plus traits—it performs exceptionally. In 2024, it generated a 56.6% whiff rate and held opposing hitters to a .201 wOBA.
The rest of Gastelum’s arsenal remains more of a question mark. His fastball sits in the low-90s and is, frankly, a below-average pitch on its own. It features a two-plane shape with modest ride and above-average arm-side run, but it lacks the velocity, life, or deception to succeed consistently on its own. He does command the pitch well enough for it to project as closer to fringe-average, though he does heavily rely on his changeup for it to be semi-effective.
Gastelum also throws a mid-80s gyro slider that flashes some promise, especially due to his spin characteristics. It has the potential to develop into an average offering, and when it’s on, it gives him another option against right-handed hitters. That said, he still shows an inconsistent feel for the pitch and it didn't perform quite as well as you would hope for in 2024. His usage of the slider is highly matchup-dependent, and it doesn’t factor into his repertoire against lefties.
He’ll also occasionally mix in a low-80s curveball, but it’s used sparingly and doesn’t currently project as more than a show-me pitch.
Future:
Gastelum’s future will ultimately hinge on just how far his changeup can carry him. In most cases, relievers without overpowering stuff struggle to find consistency in high-leverage roles, but Gastelum might end up becoming the outlier. His changeup is just so good that he could feasibly survive on the back of the pitch. Ideally, the slider continues to develop and gives him a more complete profile against right-handed bats, but even if it doesn’t, the changeup alone could be enough to get him to the big leagues and work well in matchups against lefties or changeup vulnerable hitters. Whether he ends up a middle-relief option or finds enough to work in higher-leverage situations, I feel confident projecting him to reach the big leagues and contribute in some capacity
