January 16, 2014

BP Unfiltered

RISPy Business

by Dan Brooks

Printer-friendly

Contact Author

I’m writing this blog post with the knowledge that a lot of people reading this, especially those who are “inside” baseball, will be shaking their heads at the monitor once they finish. We're used to dismissing RISP statistics because the sample sizes are too small. In this case, though, we appear to see real and meaningful differences.

Probably the most underappreciated feature on BrooksBaseball.net (at least, in terms of clicks per perceived usefulness, to my eyes) is the Pitch Usage table that can be found in the Tabular Data section of each player card. Click it, and you find a fairly detailed breakdown of when a particular pitcher uses what kind of pitch (i.e., pitch percentages split by batter handedness and count).

For example, here’s Ubaldo Jimenez’s Pitch Usage table, from MLB games last season. I’ve added some unsightly orange circles that highlight an interesting trend: Ubaldo tends to throw first-pitch sliders to RHH:

BrooksBaseball.net is a very active collaboration between myself and Harry Pavlidis; we’re constantly tinkering and adding new features to a shared database and code base. One thing we recently added to our database was baserunner information—i.e., what was the base state of each pitch. So, we added a selector to the Pitch Usage table so that you could look at changes as a function of base runners.

Check out the same trend in Ubaldo’s Pitch Usage with RISP, and you’ll see a fairly dramatic difference:

Now, he’s throwing 64 percent (!) sliders to open ABs to RHH, and only 9 percent four-seam fastballs. Of course, the opposite is true in non-RISP situations (which are also selectable):

You can see slider usage has dropped 30 percentage points, just on the basis of whether there is a runner in scoring position.

We’ve noticed some other interesting trends. For example, R.A. Dickey throws his knuckleball 75-80 percent of the time, even when the batter is ahead, with RISP, but when there’s no RISP, he’s much more likely to throw a two-seam fastball.

Or, Yu Darvish throws a first-pitch four-seam fastball at RHH only 27 percent of the time when there’s a RISP, but uses it 48 percent of the time when there’s no RISP.

I’m sure there are countless other examples. Let me know what you find!

Dan Brooks is an author of Baseball Prospectus. Follow @brooksbaseball
Click here to see Dan's other articles. You can contact Dan by clicking here