Comments on: Having Some Fun With Knuckleballer Pitch F/X

By: RCG_Robbie

RCG_Robbie — Sun, 24 Jun 2012 20:48:37 +0000

@halejon See the misidentified knuckleballs graph for some prime examples of that.

But I do like average movement overall because every pitcher works to both sides of the plate with their pitches and the average movement (along with frequency and velocity) is a way to compare different pitchers. I’ve done a lot of work with a fun variable called WVANM (weighted velocitized absolute net movement) which has an interesting association with pitcher performance.

By: halejon

halejon — Sun, 24 Jun 2012 20:40:24 +0000

@RCG_Robbie Right…sorry if sounded really negative, that’s just something I think most people don’t quite understand about the system, and the knuckle. The rest of what pitch f/x CAN tell us is interesting, and well done.

(Incidentally, average movement is problematic for other pitches too, eh? A slow change that goes up and comes back down and a hard splitter get called the same pitch all the time unless you look at the ‘Breaklength’ variable or something…Funny how hard it is to describe 3D movement with 1D numbers…;))

By: RCG_Robbie

RCG_Robbie — Sun, 24 Jun 2012 20:28:57 +0000

@halejon The big problem is the inherent limitations of using average movement. The knuckleballs move all over the place and the average movement shows so little horizontally because the movement in both directions (towards and away from the hitter) basically cancels out. I agree that Pitch F/X can’t accurately display a knuckle ball but I just wanted to see what Pitch F/X could actually tell us.
I hope that people reading this article wouldn’t just look at the graphs because without the explanations involved, the graphs are truly misleading.