The Mockingbird

Follow-up on Josh Johnson’s Curveball

with 4 comments

I probably would have done more of this if I wasn’t completely statistically gassed by the time the fact that Josh Johnson even HAD a curveball rolled around. But as pointed out in the comment, any excitement over a new pitch has to be tempered by the fact that it won’t be a novelty for long. Only time will really tell, but here’s a look at the evolution of JJ’s new pitch as the year progressed:

1a) Movement — Side-to-side (pfx)

Screen Shot 2012-12-05 at 2.40.56 PM

Pfx is where the ball ended up along the horizontal plane compared to where it would have without spin, in inches. Clearly, there is a lot of variation from one pitch to the next but also a downward trend, which means the pitch moved less from right to left as the season went on.  Also, there was less spread, which is most likely a sign of increased consistency from JJ. His first 200 curveballs had a standard deviation of 1.93, and his last 230 were at 1.79 (to try to get at what that means in baseball terms would be stupid).

Also, see that patch right over the 200 mark where every single curve is below 4? That corresponds to July 4-18, 3 starts where JJ got shelled in an otherwise excellent stretch.

1b) Movement — Up-down (pfz)

Screen Shot 2012-12-05 at 2.54.54 PM

I took the liberty of splitting these pitches up by start to address the elephant in the room — right in the middle of those three crappy starts mentioned above, Josh Johnson’s curveball dropped an extra half foot for one start (immediately after the All-star game, incidentally). Then for the rest of the season, the ‘drop’ on his curve steadily decreased. Experimenting with a new grip? Broken nail? Craft your own narrative…

1c) Movement — Bend (break_length)

Screen Shot 2012-12-05 at 3.15.41 PMLooks like an increasing amount of ‘bend’ early in the season, then a shaky patch around the all-star break, and a downward trend at the end of the season. The single start highlighted in red is his August 25 start, which was his one other blowup of the year after the break. For some reason leading into that start his curveball started to flatten out, and then was atrocious as the Dodgers pounded him for 10 hits and six runs through three innings.

I’m not trying to imply that it was all due to his curveball, but I find it really cool that there are usually completely obvious reasons for a sucky start rather than all the hocus-pocus about ‘not being sharp’, or ‘leaving a few pitches up’ we hear. I mean, of COURSE he’s not going to spill the beans on national TV after the game, but you know JJ was thinking ‘what the heck is wrong with my curveball, we gotta get on that’ after that game. Someday, every pitcher will get post-game reports like this, as umpires do (did?) with QUESTEC.

2a) Results — Miss %

Screen Shot 2012-12-05 at 4.00.04 PM

What I did here was plot for every swing whether the result was a hit or miss, and then run a rolling average (series=15). So apparently the league started to make more contact against JJ’s curve after a certain point

2b) Results — Hits

Screen Shot 2012-12-05 at 4.08.41 PM

Same thing, with hits/balls put in play. Sample size is starting to become an issue, but that’s a very clear spike in the middle of the season.

2c) Results — In Zone %

Screen Shot 2012-12-05 at 4.13.09 PM

2d) Results — Chase out of zone

Screen Shot 2012-12-05 at 4.33.49 PM

Just including these to be complete…nothing really pops out as conclusive for me.


  • Johnson tightened up his Curve into more of a pure 12-6 as the season went on.
  • He was getting more and more drop on it until the all-star break, when something went horribly wrong. From then on, that trend reversed.
  • It was getting more and more ‘loopy’ until late in the season, when again, after a terrible start, things started moving in the opposite direction.
  • The league was more and more able to make contact with his curve as the season went on.
  • This lead to more and more hits coming against it until the midway mark, at which point, yep, things reversed dramatically.

Lumping all this together, I would say that Johnson was working on making his curve more and more nasty as the league was catching up to it, and then somewhere around the mid-way point (possibly spurred on by it falling apart) wisely switched his focus to making it more controllable so he could place it more effectively. But that might be just because I know that’s what happens to every rookie pitcher and it makes sense that it would for a veteran with a new toy…

3ai) Random — average # of Strikes in count when throwing curveball

Screen Shot 2012-12-05 at 4.46.48 PM

Just a cute, not-particularly-scientific way of seeing if he was throwing it more often later in the count, i.e. a punchout pitch, as the year went on. Yep. With one crazy stretch where he gave up on it. Doing the same thing for this slider suggests that he went back to using his slider later in the count after the break:

3aii) SLIDER — average # of Strikes in count when throwing slider

Screen Shot 2012-12-05 at 4.49.57 PM

Annnnnd I’ll just bury at the very bottom of another long post a semi-apology to Bot Elliott after he clarified the Johnson #3 comment during in his online chat with: “Right now they have a lot of No. 3s or maybe Morrow is a No. 2 and Johnson could be if his shoulder allows him to add missing MPH”. That is without a doubt the most informed reason for saying that, although I still think it’s quite the bombshell to drop without any context or attempt to back it up.

Update: Ok, I take that back. Random comments from mystery men at the winter meetings is just not compelling journalism. YOU’RE IN THE HALL OF FAME, BOB. Have an opinion! Say something! Don’t just pass on this scuttlebutt like it’s this incredible inside information but you just…can’t…give up your source. Putting together that Lawrie runs and Gibby is a red light did not exactly require Deepthroat in the parkinglot, y’know?

Written by halejon

December 5, 2012 at 6:23 pm

Posted in Seriousness

4 Responses

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  1. Neat!


    December 5, 2012 at 8:44 pm

  2. […] as always, Jon Hale of The Mockingbird goes deep into the Pitch F/X to look at Josh Johnson’s curve. Must-read […]

  3. […] curve was 78.5 on average, but that doesn’t mean that it was always quite the same pitch. In a follow-up piece at The Mockingbird, Hale looked more deeply at the just the […]

  4. […] pitch  (The Mockingbird has two excellent posts analysis the pitch last season, here and here).  Johnson described his addition of the […]

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