[John Marsh]

For OOTP5, a pitcher’s ability to avoid hits determined (more than any other talent) the number of runs he would prevent. As a result, most of us would not even look at a pitcher if he did not have a “Good” rating in avoiding hits. A pitcher’s ability to prevent home runs, base on balls, and doubles mattered, of course, (in that order in fact), but it did not matter nearly as much as his ability to avoid hits.

With the advent of DIPS, however, all that changes. The question then quickly becomes what talents will matter most for a pitcher given the DIPS system? Obviously, what will matter is a pitcher’s ability to avoid home runs and walks and to strike batters out--but in what order of importance and in what proportion?

I’ve only started to work on that problem, but I wanted to see if what I’ve begun looks right to other people.

If (according to the current OOTP5 rating system) we have a pitcher with Brilliant talent ratings in avoiding home runs, avoiding walks, and striking out batters, we know that he will (if he achieves the minimum numbers for an “8” rating in each category):

(1) surrender 10 home runs per 550 at bats;
(2) give up 42 walks per 550 batters faced;
and (3) strike out 143 batters per 550 at bats.

Because avoiding walks is measured in batters faced and not at bats, we need to reduce the number of home runs and strikeouts to the number of batters faced minus number of walks given up. This would give us the following raw stat line:

AB HR BB K

508 9 42 132

This leaves 367 Balls in Play (Batters Faced-(HR+BB+K). Over the past three years, the average of balls in play that resulted in hits was roughly .2974. If we multiply that number by the number of balls in play, our pitcher will have surrendered roughly 109 hits on balls in play. Over the last three years, .228 of those hits on balls in play went for doubles and .024 went for triples. So that should give our prospect the following raw numbers:

AB H 2B 3B HR BB K

508 118 (109+9HR) 25 3 9 42 132

The estimated number of runs created for such a line is 51.2. The number of innings pitched ((AB-H)/3) is 130.0. If roughly .925 percent of all runs are earned runs, then the number of earned runs should be 47.36, which would translate into an expected ERA of 3.28.

That 3.28 expected ERA should represent the ERA of a pitcher with an “8” rating in avoiding home runs, avoiding walks, and striking out batters who pitches for an average defensive team in a neutral park, right?

The goal, ultimately, will be to figure out which categories (Home Runs, Base on Balls, Strikeouts) have more influence over expected ERA. So, for example, should you draft (all other things being equal) the prospect with a Brilliant ability to strike batters out but only average abilities to prevent home runs and base on balls? Or the prospect with Good ability across all three categories?

But I want to make sure that I understand DIPS sufficiently and that the formula I have laid out here is accurate. Any feedback is welcome.