April 15, 2004

Breaking Balls

Quick and Dirty Numbers, Pitchers

by Derek Zumsteg

the archives are now free. All Baseball Prospectus Premium and Fantasy articles more than a year old are now free as a thank you to the entire Internet for making our work possible. Not a subscriber? Get exclusive content like this delivered hot to your inbox every weekday. Click here for more information on Baseball Prospectus subscriptions or use the buttons to the right to subscribe and get instant access to the best baseball content on the web.

Subscribe for $4.95 per month Recurring subscription - cancel anytime. Subscribe for $39.95 for one year a 33% savings over the monthly price! Purchase a $39.95 gift subscription a 33% savings over the monthly price! Already a subscriber? Click here and use the blue login bar to log in.

In my last column, I wrote about how to improvise a good picture of batters from the incomplete statistics we're provided on ballpark scoreboards. Today we're going to look at pitchers.

When pitchers come into a game, we're given a much better baseline stat (ERA). We're generally also shown at least:

• W-L
  
• Saves
  
• IP
  
• K
  
• BB
  
• HR

We might also possibly get appearances, games started and complete games. Right off the top, we can toss W-L and saves into the trash. How do we evaluate a pitcher based on the remaining stats?

First, look at strikeout rate. Great pitchers run up a strikeout an inning. An average strikeout rate is about one every one-and-a-half innings, or about six a game. The worst strikeout pitchers are lucky to get a strikeout every other inning (four a game); Tom Glavine and Mike Maroth, for instance, were way down there. So if the pitcher has more strikeouts than 2/3 of his innings pitched (which is not hard to rough out), that's good. Less, bad. This is pretty easy stuff.

Walk rate is next. The pitchers that are the most generous with free passes ("OK, I've got you down plus one on-deck guest...") still only hand out a walk every other inning. An average pitcher runs about a walk every three innings. Truly stingy pitchers, like David Wells, almost never walk a batter ever. So if BB < (1/3 IP), good.

Home-run rate is important, too. Average pitchers give up a home run a game, good hurlers one every other game. The most taterific pitchers make sure some lucky fan gets a souvenir every five innings or so. There are extreme ground-ball pitchers like Chad Bradford who yield a home run once every couple of months while pitching regularly, but generally starters who suppress the long ball are still going to give it up at least one inning out of twenty - which helpfully is half of one-tenth of IP, a pretty easy calculation.

If you're interested in getting a reasonably complete picture of what a pitcher is like, taking the time to estimate their rates is well worth it. Given that, you can start to draw conclusions about the pitcher's effectiveness. Let's take some lines from last season as examples.

Player              IP        K       BB      HR
Kerry Wood         188      266      100      24
Ryan Franklin      212       99       61      34
Randy Johnson      214      294       65      12

Wood is almost a Three True Outcomes pitcher, while Franklin is the opposite: he walks few hitters and strikes out very few of them. The kid also has a bright future ahead of him as the house pitcher for the Home Run Derby. Sharp readers will look askance at that line for Randy Johnson; I threw his 1995 season in there because I want to remind people how amazing he was that year.

This three-tined approach offers us a lot more information about the pitcher than ERA does. Given that, there are other things we can infer about a pitcher. Take Franklin, who clearly relies on his defense. If he has a low ERA, you have to figure that he has a great defense behind him and/or he's been lucky. He has a decent strikeout-to-walk ratio, but both figures are low: he's serving pitches up and letting the ball go where it may. By contrast, a guy with great stuff and poor control might post the same ratio while putting up much higher K and BB totals--clearly an entirely different pitcher.

K/BB can tell us some things at a glance that are useful. A pitcher with a 3:1 K/BB ratio is trouble for hitters, and a 1:3 ratio should have them grinning from the dugout steps, tapping their shoes anxiously waiting--probably not too long--for their turn at the plate.

As we did with hitters, we have to mention park effects. Discount pitchers who do well in friendly parks and give extra credit to those who toil in Coors. It 's going to be particularly important, in some cases, to mentally adjust home run totals, so if you know that kind of information, by all means, make the adjustment.

It's pretty easy to get useful information out of the incomplete statistics given to us at the stadium, as long as you know the baselines. I hope these rough guides are of some help to you as you decide who to hail and who to heckle this season.