On the Topic of Jesse Hahn’s Success

San Diego right-hander Jesse Hahn, absent from probably every preseason top-100 prospect list everywhere, has produced four starts of considerably high quality in June — the first four starts, one notes, of Hahn’s entire major-league career. What follows is an interview conducted by the author (a noted dummy) with his own equally dumb self, for some reason, regarding the state of things with Jesse Hahn.


Managing editor of FanGraphs, Dave Cameron, encouraged you to write about Hahn today, suggesting something to the effect that he’s “your type of guy.” With the understanding that no one reading this really cares about you, specifically, explain what Cameron probably meant by that comment.

I believe what he was referring to is how I generally exhibit undue enthusiasm for the exploits of fringe-type prospects. Hahn, as one who was absent from the usual top-100 lists but who has produced results, matches that profile.

This appeal for you of the marginalized — do you suppose it’s an expression of your psychology?

To the extent that anything I do or say or feel is manifestly an expression of my psychology, then yes. Of course.

What, specifically, does it indicate about you, though, is what I mean?

I’d feel more comfortable addressing matters pertaining directly to Jesse Hahn for now. Perhaps we can discuss the matter of my psychology later?

A reasonable request. With regard to Hahn, then, what about him merits attention at the moment?

Most immediately, his short but impressive major-league resume. He’s conceded just six earned runs over four starts and 22.2 innings with the Padres. Moreover, his fielding-independent numbers, including a nearly 30% strikeout rate, indicate that his run prevention hasn’t merely been a product of the fortuitous distribution of baseball events.

That success, is it a product merely of Petco?

No. I mean, it’s possible that his raw totals are slightly better than they might have been otherwise — like if he’d made all four of his starts in Denver — but his park-adjusted numbers, including a 68 ERA- and 71 xFIP-, are also excellent.

So how’s he doing it? Is this his real talent level we’re seeing?

I’ll answer that second question first, because it’s easier. No, is the answer. Jesse Hahn will likely not continue preventing runs at a rate about 30% better than league average because almost no pitcher — with the exception, perhaps, of Clayton Kershaw or Felix Hernandez — is likely to prevent runs at that rate.

What about at a league-average rate, at least, or slightly better?

Well, the most responsible answer to that question is also not the most interesting one — which is, “Let’s look at the projections.” Steamer forecasts him to record a 3.91 FIP as a starter; ZiPS, a 4.24 FIP also as a starter. For reference, teammate Alex Torres‘s 3.60 FIP equates to a 101 FIP- and Nick Vincent’s 4.03 FIP is equivalent to a 114 FIP-. Using those figures as a guide, in conjunction with the aforementioned projections, the most likely outcome is that Hahn concedes runs at a rate about 15% greater than league average.

But he’s obviously pitched well so far. How’s he done it?

So, that’s a line of inquiry which obviously begins, and maybe ends, with a conversation about Hahn’s repertoire. Below is a PITCHf/x chart featuring the velocity versus the horizontal movement of Hahn’s pitches through four starts — as effective a way as any, that, to get a sense of what he’s throwing. I’ve outlined the most obvious of clusters to provide a basic sense of what he’s throwing.

Jesse Hahn’s pitch usage. Click to you-know-what.

So he’s throwing some combination of fastballs along with a changeup, slider, and curve?

Right, although another way of phrasing it — one which perhaps best represents his approach — is that Hahn throws either a fastball or curve 90-95% of the time. The two are about 60/30.

Would it be fair to refer to him a “two-pitch pitcher”? Because there’s generally some concern associated with deploying that sort of pitcher in a starting capacity.

Well, the problem typically concerns said pitcher’s ability to deal with opposite-handed batters. A right-handed pitcher, facing a right-handed batter, typically has the advantage. If he’s facing a left-handed batter, though, that’s more difficult. When a manager can set his lineup for the purposes of facing a specific pitcher, that’s difficult for the pitcher in question if he doesn’t have a means by which to attack opposite-handed batters.

The changeup is usually that pitch.

Yes, but it’s not the only possible one. Generally speaking, pitches with horizontal movement (like sliders) are prone to platoon splits, while pitches with vertical movement are something like equally effective against left- and right-handed batters, regardless of the pitcher’s own handedness.

So for Hahn that means what?

Well, it means that his curveball — and the degree to which it’s able to neutralize left-handed batters — is likely to inform his future success. Which, that’s somewhat fortunate, because his curveball is fantastic. Or, if not always fantastically effective, at least fantastic to watch. But, yeah, his curve has produced a swinging-strike rate of 17.1% — this compared to the league average on that same pitch of just 11.1%. Coincidentally or not, Hahn has recorded better strikeout and walk numbers against left-handed batters so far (29.6% and 5.6%, respectively) than right-handed ones (28.2% and 12.8%, respectively).

This would seem to be an appropriate time for this post to devolve really in just an exhibition of different GIFs featuring Hahn’s curveball.

Yes, other version of me. What follows are all GIFs of Hahn’s curve from June 14th at the Mets (box), which club’s home-field slow-motion camera is likely the league’s best.

A curve to Lucas Duda for a swinging strike three:

Hahn Duda

And that same pitch in slow motion:

Hahn Duda Slow

A curve to Bobby Abreu for another, different swinging strike three:

Hahn Abreu 2

And that same curve to Abreu, in slightly different slow motion:

Hahn Abreu 2 Slow

And finally, a curve for strike three looking to Mets shortstop Ruben Tejada — a pitch, this, with -15 inches of horizontal movement (according to PITCHf/x) relative to a spinless ball. About 10 inches greater of negative vertical movement, that, than the typical curveball.

With a curve like this, Hahn might be more real than his lack of a prospect pedigree suggests.

Carson Cistulli has published a book of aphorisms called Spirited Ejaculations of a New Enthusiast.

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Johan Santa
9 years ago

So… Carson’s favorite Hahn since Noodles, then?