Seth Hernandez is on Track to be MLB’s Next Top Pitching Prospect
It hasn’t taken very long for Pirates 2026 first round pick Seth Hernandez to establish himself as one of the premier pitching prospects in baseball. Given his pedigree coming out of high school as the sixth overall pick in last year’s draft class, Hernandez came in to pro ball as a big name to follow this spring, but the early returns on him have already exceeded expectations. Just four starts into his professional career and he looks to be on track to be the third consecutive Pirates first round pick to rocket up prospect rankings, following Paul Skenes in 2024 and Konnor Griffin a year ago.
High school pitchers are the draft demographic that typically take the longest to develop, and for that reason, they usually stick around in Low-A for the entirety of their first pro season. Four different prep arms were taken in the first round in 2024 (two of which came in the supplemental round), Cam Caminiti (24th, ATL), Kash Mayfield (25th, SDP), Braylon Doughty (36th, CLE), and Levi Sterling (37th, PIT). Aside from Sterling spending the majority of 2025 in the Complex League, neither Caminity, Mayfield, or Doughty advanced past Low-A despite impressive debut seasons there. A year later and Hernandez is looking like the exception to the rule with the way he’s toying with hitters in the Florida State League.
In 17 innings across four starts, the 6’4” right-hander has allowed just one earned run on four hits and five walks, good for a 0.53 ERA, 0.53 WHIP, and a .074 batting average against. The success thus far all stems from his ability to miss bats due to his high-end stuff. He has struck out 32 hitters, or 53.3% of the hitters he has faced, a mark that currently leads all Minor League pitchers regardless of age or level. He’s also walking just 8.3% of hitters, giving him a 45.0 K-BB% and a 1.09 FIP, both of which rank within the top three in all of Minor League Baseball.
The arsenal starts with the fastball, but what really separates Hernandez from other pitching prospects his age is his feel for his secondaries. Beyond the fastball, there’s two, and maybe potential for three, plus pitches in the mix for Hernandez. It’s a changeup, slider, and a curveball, all three of which he’s using between 14% and 18% of the time. Across his three secondaries, he’s running a ridiculous combined whiff rate of 73.3% and a swinging strike rate of 40%. Those numbers are also boosted by the fact he’s inducing a 47.6% chase rate across those pitch types. The premier secondary in Hernandez’s pitch mix is the changeup that made him such an intriguing draft prospect, but it has arguably been the curveball which came in to pro ball third in the pecking order that has performed as his best pitch. Throwing it 14.1% of the time, he has returned a 91.7% whiff rate and a 35.5% swinging strike rate on the pitch. It’s still a smaller sample size having thrown only 31 curveballs thus far, but it’s tough to deny 11 whiffs on 12 swings. Stuff models aren’t particularly high on the curve, but it has been a pitch that he has located well, and it plays great off the rest of his mix. Averaging 80 mph, it gives Hernandez a fourth velocity band as the fastball works in the high-90s, the slider in the high-80s, and the changeup in the mid-80s. At roughly -10.5 inches of induced vertical break, it’s also averaging about 25-27 inches of vertical separation off of the fastball, and is also his one pitch with significant depth as the slider works best as a bullet shape and the changeup is closer to 10 inches of IVB.
As expected, the slider has been excellent, returning a 72% whiff rate and a 45% swinging strike rate. It’s averaging 2.7 inches of IVB and -0.5 inches of glove-side break at 88.4 mph, giving hitters a true bullet or cutter look. It plays so well due to his ability to spin it. In his four starts, he’s averaging 2621 RPMs, but in his most recent start for Low-A Bradenton, ran it up to 3178 RPM. For reference, the average spin rate on an MLB slider thus far in 2026 is 2429 RPM. It’s his most used secondary right now, throwing it 18.2% of the time - 26.2% of the time to right-handed hitters and just 8.8% of the time to left-handed hitters as the changeup is the go-to against lefties.
Although the changeup lacks in exciting characteristics, it’s still Hernandez’s best executed pitch. It’s running a 65.2% whiff rate and a 38.5% swinging strike rate. He doesn’t really kill spin on it as it’s averaging 2253 RPM (the best offspeed pitches are usually <2000 RPM), and it’s shape is merely average at 9.5 IVB and 14.5 HB, but like the curveball, it stands out because of its velocity and vertical separation off of the fastball, and his ability to locate it. It might actually be the pitch located best by Hernandez which is rare given it takes a lot of time for young pitchers to really develop solid feel for an offspeed pitch.
The secondaries have been the most effective pitch types for Seth Hernandez, but that’s not to say that the fastball has been a non-factor. He’s throwing it 50% of the time and averaging 97.5 mph on it. He has popped triple digits with it three times, maxing out at 100.5 mph. He was also up to 102.4 mph with it in a shorter outing at Spring Breakout in March. The shape on it is closer to “dead zone” rather than an elite shape, but the shape becomes less and less significant the more he’s consistently sitting in the upper-90s with it. He’s dropping it in the strike zone 54.5% of the time, and while its 23.9% whiff rate is down considerably below his secondaries, opposing hitters have only returned a .230 xwOBA, .177 xSLG, and a .145 xBA on it. Those numbers almost certainly won’t hold as he advances into the upper minors, but the early returns on the fastball are encouraging nonetheless. As he advances, he’ll have to lean on the fastball less and really learn to use his secondaries more. Given his success with them thus far, that is why he projects as a prospect so well. The pitch-ability is going to improve, the strike-throwing will only get better as he learns to repeat his mechanics, and the stuff will only get sharper as he still has a lot of room to grow into his 6’4” frame to add more strength. With all of that being said, don’t be surprised if Seth Hernandez finds himself at the top of pitching prospect rankings by the end of the year.
