Jack Flaherty, still just 28 years old, has already endured more ups and downs than most pitchers do in their entire careers. His peak, a 4.7-win, fourth-place Cy Young finish in 2019, tells a story far different from the middling 3.3 WAR he’s accrued in 299 innings sandwiching a variety of injuries since. What should we make of the former heir apparent to Adam Wainwright?

Let’s start by asking how teams are assessing him, now that we have at least one more data point. The Tigers evidently see enough in the erstwhile ace to fork over $14 million for a year of his services, with games-started-based incentives that could tack on an additional $1 million. Incentives aside, his age and upside helped him net the largest guarantee for a starter on a one-year deal so far this offseason, outpacing the likes of Luis Severino, Kyle Gibson, Lance Lynn, and Wade Miley. Among two-year contract recipients, his AAV is higher than that of Erick Fedde, Nick Martinez, Tyler Mahle, and teammate-to-be Kenta Maeda.

Before the Tigers, it was the Orioles who opted to take a flier on Flaherty. It cost them a trio of prospects at the trade deadline, though none that our Eric Longenhagen saw as more than a 40 FV player at the time. In seven starts for Baltimore down the stretch (he also had a pair of relief appearances), Flaherty improved his K-BB% by about five points and bumped up his fastball velocity, movement (rise and run), and usage. Thanks to these improvements, his fastball saved him runs as an Oriole after costing him big as a Cardinal, and it once again approached the shape that it took in 2019:

But Flaherty’s top line results still worsened in Baltimore, likely due to his slider, which trended in the opposite direction post-trade. Whatever tweak Flaherty made that resulted in a hotter heater may have also been behind an uptick in slider velocity, one that outpaced that of his fastball. This not only resulted in a narrower velo gap between the two offerings (the 8.4 mph gap was smaller than in any previous season), but his slider also lost over an inch of drop and sweep each:

The synergy of his fastball and slider has been crucial to the right-hander’s success; they’ve only saved Flaherty one run per 100 pitches in the same season once — in his career-best 2019 year. This season didn’t join 2019 as an exception, as one pitch seemingly only experienced success at the expense of the other.

So, Flaherty may have gotten his fastball back with the O’s but lost his slider in the process. What of the knuckle curve, his preferred tertiary offering? Similarly, it gained a couple of ticks after the trade, narrowing its velo gap with both the slider and the four-seamer. Adding more sweep to it made the pitch Flaherty’s best weapon in 2022, and it was successful again in ’23 pre-trade. But when Baltimore got a hold of the pitch, it lost some of that cut and became a costly offering again.

All three pitches trended in the direction of more arm-side run after the deal, which, similar to the velocity increases, only benefitted the heater. Strangely, Flaherty has shown a tendency to cut his four-seamer throughout his career, with below-average arm-side run and spin efficiency on the pitch; pushing for more arm-side run seems counterintuitive for a pitcher who likely has a supination bias, yet the spin efficiency on Flaherty’s four-seamer has only decreased since Baseball Savant began tracking it in 2020. Assuming this trend began before then, it’s likely that his most spin-efficient four-seamers were his most successful.

Perhaps the Orioles added more spin efficiency to his fastball, which I can only guess at since Savant doesn’t offer spin efficiency splits. They could have done this through changes in wrist/forearm action or finger placement/pressure, since there were no discernible changes in arm slot. Whatever the alteration, it may have spilled over to his breaking balls, decreasing their cutting action, too. But that change was clearly undesirable for the secondaries.

Former teammate Kyle Bradish made the cutting four-seamer and breaking-ball-heavy approach work in 2023, but he has an elite slider and a plus curve; Flaherty’s secondaries are merely average by shape. How this profile worked earlier in his career I’m not sure, but whether it’s the (slightly) decreased velocity, failing to find that goldilocks zone of spin efficiency that benefits both the slider and four-seamer, or something else, what’s clear is that the strategy isn’t working anymore. In my mind, the most sustainable choice for the supinator would be to lean back into that natural strength.

If the Tigers and Flaherty choose to do so in order to recapture his breaking balls, the hurler might benefit from using his actual cutter more than his cutting four-seamer — on a per-pitch basis, per run value, the cut fastball has outperformed the straight heater in each of the past two seasons. If there’s concern about the cutter bleeding into his current slider, developing a sweeper could be a useful gambit; that would put more distance between Flaherty’s put-away pitch and his primary fastball, with the knuckle curve still coming into play as a weapon against lefties due to its relative platoon neutrality. Plus, sweepers are easier for supinators to develop, as they’re naturally inclined to get on the side of the ball.

Trying to fix Flaherty has been a game of whack-a-mole these past few years, and I’m not going to pretend that I’ve unearthed the answers major league orgs haven’t. Especially since the Orioles have become better at developing pitching since Mike Elias took the reins (and moved the left field fence back); they very well might have kept tweaking until Flaherty returned to form if they had the time. Maybe they even would have had him develop an entirely new pitch (like a sweeper) if they didn’t have to do it in the middle of a playoff race. Still, their lack of success indicates there’s probably no quick fix for the right-hander.

Now, the Tigers will get their chance — with some offseason left and a full season ahead — while the hurler can still be had for a relatively cheap sum. Whether he ends up a serviceable option is anyone’s guess, but Detroit surely has a plan solid enough to warrant spending a decent chunk of change.

Source