There is a thread at Sons of Sam Horn entirely devoted to talking about Jon Lester.

This is odd, because it is against their policy of megathreads, but if you're looking for some retrospective analysis of Jon's stuff over the course of the season, you could just compile that and post it on the web. A friend and I are planning to do that, just after I manage to crawl out from the mound of papers currently stacked up on my desk (note: if my advisor is reading this, it's my first blog post in a month, really).

Anyway, a recent discussion was about whether or not Jon was getting stronger as the season went on. Fair question. Here's my post on the issue:




The first figure is simply a graph showing his average fastball velocity and average curveball velocity over the course of the season, for all the games except Philly (their system is pretty clearly broken).

There's a steady rise in both Fastball and Curveball velocity, suggesting that the rise in fastball velocity isn't due to a change in fastball type distribution.


The other graph is a bit more psychadelic, so here is the explanation. I realize that averaging across pitch types can be bad because of the known issues in trying to identify pitches, so I took one of his first starts from each month of the season and plotted each pitch on the same Horizontal Movement X Speed axis. To account for the fact that different systems may have slightly different speed readings I used his first start at Fenway for each month.

Warmer colors (yellows and oranges) are early in the season, cooler colors (blues and purples) are later in the season.




I think it's pretty clear that the velocity increase is not due to pitch misidentification or something else, as the velocity increase is really across the board. Cooler colors are clearly above warmer colors in each cluster in this figure.


For those struggling to identify these pitches I have labeled them.

1. Bottom Left (Ugly Dark Purple) - Curveball
2. Middle Left (Light Blue) - Cutter (a few sliders towards the curveball side)
3. Top Middle (Green) - 4Seam Fastball [a few changeups are thrown with this kind of movement and erroneously grouped in the circle, they are the very slow 4seam fastballs, sorry]
4. Top Right (Light Purple) - 2Seam Fastball
5. Bottom Right (Orange) - Changeup