The Mariners have drafted and developed an entire rotation in just five years

TINSTAAPP. It hasn’t quite hit the working vocabulary of baseball fans the way TOOTBLAN has, but TINSTAAPP has become axiomatic in amateur and minor-league coverage. There Is No Such Thing As A Pitching Prospect. It’s meant to capture the idea that pitching prospects flame out at a much higher rate than position players. Development is harder, injuries more common. But you say TINSTAAPP and Jerry Dipoto says, “Challenge accepted.”

Now that Emerson Hancock has made his MLB debut, the Mariners rotation this year features five starters that this regime drafted over a four-year period, developed, and turned into MLB-quality arms. That’s an entire rotation’s worth of organizational success, all debuting in just a 27-month span. And while the most credit belongs to the players themselves, all parts of the organization deserve some praise here.

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Start with Scott Hunter and his team’s identification of these talents. Logan Gilbert, George Kirby, and Emerson Hancock were all first-rounders, but not obvious choices. Gilbert’s velocity dipped his junior year, but the Mariners were the ones who weren’t worried (turned out he had mono) and pounced when he slid down the draft board. Seattle was the team that thought Kirby, a command artist from a small school with a thin record against elite competition, could be something great. And while Hancock was once thought of as a potential first-overall pick, other teams gave up on him during the pandemic and the Mariners didn’t, nabbing him with the sixth pick. Bryce Miller and Bryan Woo, a fourth- and sixth-rounder, respectively, were picked late enough that you’d never just assume they’d have MLB careers.

As for the development, Brian DeLunas, Max Weiner, Trent Blank, and their teams didn’t just implement a copy-and-paste job. They helped Gilbert develop the slider and splitter that play off his extension-aided fastball to maximum effect. Kirby already had pinpoint command, but they amplified that by bulking him up to add the velocity that makes the whole package All-Star worthy. They helped Miller command his otherworldly fastball so that, high-wire act that it is, he’s getting through MLB lineups without a real secondary. They had the confidence in Woo to promote him with just 101 pro innings under his belt, and they were right. And in Emerson Hancock, they worked patiently to help him develop a changeup and slider that can compensate for the surprising lack of swing-and-miss on his fastball. To me, that one’s the most impressive. It seems like they miscalculated in thinking Hancock could be a strikeout king, but they adjusted and turned him into something good enough for The Show anyway.

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No shade to a strategy like having someone teach the same pitch to everybody in his path. If that pitch works as well as the Warthen slider does, for example, then by all means, go forth. But in my view, the degree of difficulty in nurturing five different talents deserves some extra praise.

Of course, it’s not necessarily better to have built these five guys from the ground up. Identifying and acquiring Luis Castillo, Robbie Ray, and Marco Gonzales works too. But even though Ina Garten says that store-bought is fine, we all know there’s something extra satisfying about having grown your own tomatoes. And by drafting these pitchers, you avoid paying top-dollar for pitchers in their 30s, when injury risks and declining skills become more common. This year’s trade deadline—where pitchers in their 20s with multiple years under contract were the hottest commodity around—serves as proof of just how valuable the Mariners’ success is.

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Meanwhile, the other 2023 team that’s used five of their own drafted starters just goes to show how impressive the Mariners’ work has been. The Royals have used five starters who they drafted in Brady Singer, Daniel Lynch, Alec Marsh, Kris Bubic, and Austin Cox. You could also count Zack Greinke if you wanted. But the Royals rotation has an ERA over five. By just about any metric, it’s a bottom five staff, compared to the Mariners, who are at the top of the league.

So too does a Mariners’ division rival remind us that churning out home-grown pitching isn’t a given. In 2021, Anaheim used all 20 of their picks on college pitchers, specifically sacrificing upside in exchange for the hope that they could get some hurlers to help out the big-league squad as soon as possible. Out of those 20, just Sam Bachman and Chase Silseth have debuted. You see, there is no such thing as a pitching prospect.

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To be sure, this battlestation is not quite fully armed and operational. Woo and Miller are outrunning their scouting reports, trying to develop faster than the league can figure out how to hit their fastballs. Woo’s had more success than Miller, but also just hit the IL (though many suspect it’s a phantom IL stint to manage his innings). And Hancock is just a single start into his MLB career. We’ll have to wait and see before we declare him a Kirby- or Gilbert-level success. But while this is the beginning of something, in another sense, it’s also the end, and congratulations are in order. What the team has done in getting these five guys onto the T-Mobile mound is truly remarkable, and the organization deserves a victory lap.