The Return of the Koji Uehara Curveball

Every pitcher in baseball has a primary pitch, and for almost every pitcher in baseball, that’s going to be some variety of a fastball. After the primary pitch, there will be an assortment of secondary pitches, numbering from one to a lot more than one. But not all secondary stuff is created or treated the same; there can be a trusted secondary pitch, or a decent secondary pitch, or a rare occasional secondary pitch. Clayton Kershaw‘s slider is a trusted secondary pitch. Tony Cingrani’s slider is a decent secondary pitch. You have to keep your eyes peeled for the occasionals.

Plenty of guys throw them. Let’s look at some examples! Here’s Danny Salazar throwing a terrible curveball:


Here’s Brad Boxberger throwing a better curveball:


Here’s Phil Hughes throwing a rare changeup:


Guys mix things in. C.J. Wilson has toyed around with a knuckleball. Sometimes it’s just a gimmick. Sometimes it’s a test of something a pitcher has been working on in the bullpen. An occasional tends to be just an occasional, but they’re incrementally more exciting than other pitches, and Koji Uehara happens to have an occasional of his own. A year ago Uehara threw three curveballs, and they were written about, as they were his first curves in the majors since moving out of the rotation.

The curve wasn’t a great pitch for Uehara. The curve didn’t need to be a great pitch for Uehara, because he already has one of the best splitters in the world. Last year he threw all three of his curves as the first pitch in at-bats during one-sided games, I guess just to see, and he didn’t try one after July. It wasn’t something that mattered for him, but now I have news that you might care about: Uehara’s curveball has been sighted again. Definitely once, maybe twice, after more than a full year went by.

So we can get right to this. According to Brooks Baseball, Uehara this year has thrown the curve twice. It’s believed he threw his first of the season last Tuesday, against the Reds. Let’s take a look at the pitch:


Well, it doesn’t seem like a curveball. Reasons to believe it was a curve:

  • first pitch of an at-bat
  • identified as a curve by Brooks Baseball

Reasons to believe it wasn’t a curve:

  • one-run game!
  • unusually fast for an Uehara curve
  • not identified as a curve in our game log
  • didn’t move like a curve

What we know, at least, is that the pitch was bad:


And it was neither an Uehara fastball nor an Uehara splitter:


That looks like three fingers, and for Uehara, three fingers means a cutter. Uehara throws a cutter, sometimes, and it does kind of what that pitch did, so the likelihood is that, on August 12, Koji Uehara threw several pitches but zero curving pitches. Yet Uehara pitched again on Saturday. Saturday brought another suspicious pitch.


Brooks Baseball identified this as a curve. Our game log identified this as a curve. The movement and velocity match up with Uehara’s infrequent curves, and you’ve also got this being the first pitch of an at-bat in a lopsided game. As for the sign:


It seems like three fingers, but I’m almost certain it’s four fingers, and we’re forced to stop short of true certainty by pixelation. But it looks like a curveball visually, and it was a pretty good one, for that matter:


For further confirmation, Texas Leaguers comes in handy. From an Uehara 2013 PITCHf/x chart, the outlier curveballs are easy to spot:


Now here’s 2014:


Two pitches are identified as curves, but one of them stands out and the other one of them hangs near the infrequent cutters. They’re separated by six miles per hour, which doesn’t prove their differences — especially given that this isn’t a pitch Uehara has confidence in — but which does strongly suggest them. By the way, because you probably noticed it, that point above the cutters all by itself is a glitch. That’s not a separate Koji Uehara occasional. His occasional is his curveball, and from the evidence it looks like he just threw it for the first time all season on Saturday against the Astros.

Why throw it? I mean, I don’t know — this year, as last year, Uehara doesn’t need the help. He’s not going to figure anything out throwing a pitch once or twice per season. But then, one of the understood keys to happiness is variety from your routines, so toying around with a curveball might work somehow to Uehara’s psychological benefit. To put it simpler: maybe it’s just fun, and, who knows what might happen? What’s the harm, in a lopsided game in a lost season? Last year, Uehara threw a curveball and hit a batter for the first time in his major-league career. He probably didn’t want to leave it like that, so he tried it again later on and got a called strike. Maybe it’s just a very minor side project, and he’s trying to get a whiff. I’m not certain why there are occasionals — I’m just glad there are occasionals.

And the absolute most amazing thing of all? Uehara, for the first time all season, threw a curveball, and he threw it as the first pitch to Dexter Fowler to try to get a surprise strike. Fowler not only swung at the curveball — he made contact, solid contact, and lined out to deep right field. Dexter Fowler got one of the most rare pitches in baseball, and he attacked it and killed it. Which leads one to wonder: will we ever see the Uehara curveball again? On the one hand, we saw it again after the hit-by-pitch. On the other hand, maybe it’s not as surprising as it sounds like it should be. After the previous one worked out, Uehara didn’t try another curve for more than a calendar year. I’m not really sure how many calendar years he has left.

We hoped you liked reading The Return of the Koji Uehara Curveball by Jeff Sullivan!

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Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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I don’t get it.
Slow day.