THE BOOK--Playing The Percentages In Baseball

From the article: “As you might think, if one pitch is at the same speed as the other one but has more break, it’s harder for the hitters to make contact. However, that’s actually not the case here. The percentage of swings and misses induced by the sinker is, surprisingly, much lower than that of the fastball, and it’s also much easier for the hitters to put a sinker in play.”

Fastballs have positive break in the sense that they don’t drop as much as we’d expect from gravity, no? If that’s the case, is it possible sinkers are easier to hit because their break is more in line with a natural drop? In other words, with a four-seamer a hitter will subconsciously assume a certain vertical break and end up swinging under it, but the sinker comes closer to the perceived path so they make contact. If that makes sense.

The next question: What happens to a sinker (or fastball) when it’s actually put into play?  And are there variations by pitcher.  (Who has a “good” sinker in that it actually becomes a ground ball most of the time and whose sinkers get hammered?) Ah, so much data to mine, so little time.

What Anthony said.  A good four-seamer is a swing-and-miss pitch, because even a major-league hitter tends to swing under it.  Watch enough replays of good swing-and-miss fastball pitchers and convince yourself.  This result is good science: it confirms casual observation with data.

The question, then, is why the two-seamer can be effective—why it is a groundball pitch.  The answer, I am pretty sure, lies in the simple mechanics of the batter’s swing and the ball’s location.  Viz (on a slightly different subject, and using far too many words to make the point, but otherwise good), http://www.hardballtimes.com/main/article/why-flies-go-one-way-and-grounders-go-the-other/

He couldn’t distinguish Penny’s 2 seamer from his 4 seamer, and honestly, there doesn’t seem to be a categorical difference between Burnett’s, either.

It would be interesting to see some statistical tests for the linear effects of speed, horizontal break, and vertical break on contact rates, instead of arbitrarily lumping them into two groups.

Hat tip to Dan Fox, here’s a summary of gameday articles:

http://fastballs.wordpress.com/2007/08/01/summary-of-enhanced-gameday-analysis/

I’ve linked to some of those here:
http://www.insidethebook.com/ee/index.php/category/Ball_Tracking/