Pitcher Contact% and Strikeouts in 2009

Though it’s quite brief, I have to believe that Jeff Sullivan’s post on the correlation between pitcher contact rates and strikeouts from this past August has got to be one of the most exciting of the year. It makes so much sense — miss bats, get strikeouts — and yet Mr. Sullivan appears to be the only one on the interweb (besides our own Matthew Carruth) asking substantive questions about it*.

*If there are others, please don’t hesitate to mention them below.

You can see the correlation between the two in this image I’ve stolen directly, unforgivably from Lookout Landing:

That’s pretty striking. And it begs a question: If the correlation between Contact% and pitcher strikeouts is so strong, then couldn’t Contact% help us understand which pitchers might be poised to top the strikeout charts next year?

Yes. With some caveats.

In that same post to which I’ve linked above, Sullivan also notes that, beyond Contact% (league average 80.5%), pitchers also control their strikeout rates by other means, such as First-Pitch Strike% (league average 58.2%), Zone% (league average 49.3%), Called Strike%, etc. While none of these factors correlate as strongly as Contact% to pitcher strikeout rates, it does appear as though they’re not entirely negligible, either. To that end, I’ve included the first two of those below for comparison’s sake.

What happens when we run the 2009 numbers for Expected K%s (xK%)? That’s the question I asked myself — and which I answered, I think, by means of the kinda dumpy looking table you see below. Here are the Top 10 starting pitchers (50+ IP) by Contact% with expected and actual strikeout rates, plus K/9:

So, what do we see here? Some likely suspects, for sure: Harden, Lincecum, Vazquez, de la Rosa. But also some surprises: Felipe Paulino (second!), Gio Gonzalez (third!), and Bud Norris. The first two of those guys I wrote about last week as tRA* surprises. Bud Norris I didn’t mention, but he actually finished 66th in tRA* out of the 183 pitchers with 150+ xOuts.

What conclusions can we draw from this? Well, we should probably be careful about that, as more research needs to be done in this area. Still, it’s probably reasonable — given his xK% and overall profile — to expect at least a small improvement in strikeouts from Felipe Paulino. Moreover, there’s reason to think — given his excellent Zone% — to think that Bud Norris will probably turn some of his walks into strikeouts.

How well do you think Norris will perform in 2010? Enter your Fan Projection here.