How Real Is Jack Flaherty’s Resurgence?

Jack Flaherty's comeback might be for real this time.

I don’t think anyone thought this would be the discussion to be had about Jack Flaherty a few years ago. He’s had such an up-and-down MLB career to this point after looking like an ace in 2019. We’re talking about him now as he’s once again trying to regain his old form. This time might actually be different though, as he’s made some notable improvements. We’ll dive into what he has to offer and how he can use it to be a bit more like the Flaherty of old.



The Fastball


Flaherty, like most pitchers, leads with his fastball. Luckily for him, he has a good one. His fastball still averages 93.8 mph, which isn’t a far cry from what it was in his best season. His top velo is still the same as it was then, he just manages his stamina a bit more now. He has a lower-than-average release at 5.4 feet off of the ground, with less overall movement than most four-seams. However, most of that movement is vertical with 15.3” of induced vertical break, and just 2.9” of induced horizontal break. This is enough rise at that release height to create a reasonably flat zone neutral approach angle.

Unfortunately, he has a bad habit. He doesn’t elevate this pitch anywhere near enough, limiting its effectiveness. He’s good at locating it on the sides of the zone but without throwing it high it will never miss as many bats as it could. It will also be subject to batted ball quality that’s less than ideal for the pitcher. It’s not the worst case of pitchers doing this, he doesn’t throw it right down the middle to challenge hitters, he just hasn’t optimized his strategy with this pitch. As it stands, I’d call it league average with the potential to be better.


The Slider


This is probably Flaherty’s best pitch. It’s not the most unique slider but, in terms of stuff, it’s solid. It comes in at 85.1 mph, with 2.1” of induced vertical break, and 6.9” of induced horizontal break. From his release point, this isn’t special but it doesn’t need to be, most sliders that suppress this much iVB are good. It also fits well into his arsenal.

More important than the stuff for this pitch, Flaherty’s ability to command this pitch is phenomenal. I’m working off of a small-ish sample of 240 pitches, but it’s an impressive 240 pitches. He’s been drilling his spots right below the zone to elicit chases and whiffs. When he does miss, he misses low, which can still potentially get a chase, but more importantly, it’s not a miss that can lead to hard contact. His mistake rate is just 4.7%, compared to the league average of 7.3%. His command of the slider so far this season has elevated this pitch to near elite level.


The Curveball


This pitch puzzles me a bit. It’s not particularly great from a stuff standpoint. He throws it 77.8 mph but with a wide range slower and faster. It averages -10.4” of induced vertical break, and 14.6” of induced horizontal break. This isn’t a shape I’d normally be fond of, but it’s missing bats and it always has for him. It may be pushing to a point of having so much movement that it doesn’t matter if the direction isn’t optimal, it’s still hard for hitters to track. It does have more than a foot of sweep so maybe I’m being too hard on it, it just doesn’t fit into the normal sections on a movement chart that I think of positively.

Like the slider though, this pitch is substantially elevated by his ability to locate it. He’s done an excellent job this year of dropping this pitch right around the low arm-side corner. He hasn’t gotten many called strikes with it, but its chase rate has been ridiculously high. Clearly, he’s doing something to fool hitters with it. Similar to his slider, he isn’t missing in bad spots with it. His mistake rate of 3.1% is well below the league average for curveballs.


The Changeup


A pitch he uses almost exclusively in platoon matchups, Flaherty throws a changeup that’s more of a developmental offering. He’s never had much command of his changeups and the current version is no different. The shape is decent at 86.1 mph, with 5.1” of induced vertical break, and 11.8” of induced horizontal break. When he’s feeling it, he can locate it off the zone on the arm-side so it looks like a hittable fastball until it fades away from lefties and out of their reach. More often though it just misses and hitters don’t have any issues spitting on it. It could be something if he keeps working on it but it’s a distant fourth offering at present.


The Sinker


A pitch that used to be a much bigger part of his arsenal, Flaherty has all but shelved his sinker. It only works in that it’s deceptive and it spins on the same axis as his fastball but has drastically different movement due to seam-shifted wake. That different movement isn’t great though. He throws it less hard than his four-seam at just 91.1 mph this year, with 8.9” of induced vertical break, and 10.9” of induced horizontal break. Honestly, the only use for this pitch is to try to tie up right-handed hitters by running it in on them and that’s largely what he’s tried to do with it. He’s using it about ~2% of the time and it should probably stay that way.


The Outlook


Flaherty’s numbers this season aren’t sustainable. This is both a bad and good thing. His 32.1% strikeout rate compared to his 3.1% walk rate will not hold up over the course of the season. Even if he’s fully earned those numbers to this point, that ratio is bound to regress a bit. However, he’s due for some positive regression as well. He’s had some tough batted-ball luck, especially on the slider. That will likely even out if he keeps throwing it as well as he has been.

Some concerns come with being essentially a three-pitch starter with two of those pitches being breaking balls. However, Flaherty has managed to be mostly platoon-neutral across his career despite this. His usage of his main three pitches against righties and lefties is largely the same, which is remarkable. It bodes well for his future that he can do this and find success with it.

The biggest thing for Flaherty is going to be improving the way he uses his fastball. It’s gotten hammered on contact this year because he isn’t giving it its best chance to succeed. Something to watch for start-to-start is where he’s locating it. If he’s just filling the zone, that’s a semi-acceptable disappointment. If he’s elevating it, that’s a sign of promise.

The rest of it for him is mostly going to be about trusting the process. His stuff is good, and it’s largely working. He’s missing bats constantly, he’s making hitters beat him, and he’s not suffering as much stuff flux as he has in the past. There’s a lot to like about what he’s been doing, he just needs to keep doing it.

Jack Foley

Jack is a contributor at Pitcher List who enjoys newfangled baseball numbers, coffee, and watching dogs walk by from the window where he works. He has spent far too much time on the nickname page of Baseball-Reference.

Leave a Reply

Your email address will not be published. Required fields are marked *

Account / Login