Comments on: One Win Curveballs

By: Bhaakon

Bhaakon — Fri, 26 Jun 2009 22:40:53 +0000

Could it be the situations in which the curve is used? I’m not terribly familiar with pitch f/x data, so I don’t know if it supports this, but my perception of conventional baseball wisdom is that curves (really, all breaking balls) with large horizontal movement are more effective when the movement takes them away from the batter, and less effective when it moves towards the batter. Hence the proliferation of LOOGY’s with “frisbee” breaking balls.

I’d be interested to see a platoon breakdown of these pitches value. It probably wouldn’t mean much for Penny, but I wouldn’t be terribly surprised if (and these are totally invented example) the value of Wainright’s curve comes almost exclusively against right-handed batters, or Moyer’s from lefties.

By: Dave Allen

Dave Allen — Fri, 26 Jun 2009 19:19:53 +0000

That is really interesting, I will have to look at that. Maybe recreate my one plot but with vertical location rather than movement.

By: Nick Kapur

Nick Kapur — Fri, 26 Jun 2009 18:00:04 +0000

Maybe this is an ignorant comment, but I wonder what effect a pitcher’s other pitches has on their curveball effectiveness. Can we really isolate a pitcher’s pitches like this, without reference to the rest of his arsenal. For example, if Roy Halladay has a really great fastball, does that make his curveball better, even if it is not “objectively” better (as measured by break, velocity, etc.)?

And like the last commenter, I also wonder about location. From subjective observation, when Brad Penny is pitching well, he keeps his fastball up in the zone and his curveball down, but when he throws his curveball up in the zone, it usually gets crushed.

By: Choo

Choo — Fri, 26 Jun 2009 16:57:38 +0000

A soccerball is easily compressed when kicked and is not smooth – it has tiles and stitches.

By: Dave Allen

Dave Allen — Fri, 26 Jun 2009 14:55:39 +0000

The value of each pitch is taken as the run expectancy after the pitch minus the run expectancy before the pitch. If you sum the value of all of their curveballs you get over ten runs saved.

I am not sure about Penny’s curve. It is much worse this year than ever before, it could be a small sample size issue, but he has thrown over 250 this year. It could be because his movement is so close the average curve movement.

By: Alan Nathan

Alan Nathan — Fri, 26 Jun 2009 14:00:17 +0000

Re Ryan and his link: What is needed to get a knuckleball effect is a non-smooth ball. For a baseball, the seams serve that purpose. While a soccer ball (as shown in your link) has no seams, it is far from smooth.

Re curve ball movement: I am wondering if location is more relevant than movement. In particular, a hanging curveball might have lots of movement but will get crushed if left high in the zone. I recall having looked at hanging curveballs a year or so ago and found that the movement on them was not different from better curveballs but the location was high. I don’t recall now if there was a correlation with release point or perhaps initial velocity direction.

By: VidaB

VidaB — Fri, 26 Jun 2009 12:34:48 +0000

Great article, thanks! The last bit about high movement / less effective curves made me curious. I’d love to see if you investigate what other variables account for that.

My first thought was accuracy. But I’m not sure what would be the right measure for that. Balls/strikes came to mind, but a good curve might be one that looks enticing but then breaks out of the zone. So maybe O-swing %?

But my second thought was velocity-relative-to-fastball, so that a bigger differential messed up the hitter’s timing more.

Any other independent variables to test out? Again, I’d love to read a follow-up piece that breaks this down even further. Because who can get enough regression analysis?

By: Ryan JL

Ryan JL — Fri, 26 Jun 2009 01:23:54 +0000

Here is some evidence that the knuckleball effect can be achieved without seams:

http://www.youtube.com/watch?v=mX0y1kumtss

By: Dave Allen

Dave Allen — Thu, 25 Jun 2009 22:31:09 +0000

Unfortunately I think that little blob far off to the right are a mistake. For some ball parks the pitchf/x system was calibrated perfectly. I am working on going back and correcting for it. It was particularily bad last year at the Great American Ballpark and Bronson Arroyo has a curve with lots of horizontal movement. So I think that blob is from Arroyo’s home curveballs.

By: Dave Allen

Dave Allen — Thu, 25 Jun 2009 22:27:00 +0000

1) I use the square root of the sum of horizontal movement squared and vertical movement squared.

2) Like TomG I assume you get that little bump at the average curve movement.

3) I wrote an article at baseball analysts about that. I think that the horizontal movement is important in same-handed at-bats and vertical in opposite-handed.

http://baseballanalysts.com/archives/2009/04/the_breaking_an.php