Baseball has gotten a lot of mileage out of ERA over the years, and it continues to right now. It's a fine stat but it has its limitations; mainly a pitcher can't really control what happens to a ball put in play. So we have FIP or DIPS, which tend to take pitching evaluation to the opposite extreme: they only measure Ks, BBs, and HRs.
So the question becomes how to balance the two, and fortunately somebody developed an answer. It comes from Graham MacAree and Matthew Carruth at StatCorner.com.
tRA involves assigning run and out values to all events under a pitcher's control and coming up with an expected number of runs allowed and outs generated in a defense and park neutral environment. tRA is on a R/9 scale and does not involve any regression of the rates so while it should be more useful at determining a pitcher's true talent level, the best method for pitching projection is to use tRA*, the regressed version of tRA.
Here's the numberless explanation. You might have heard it discussed elsewhere in the baseball blogosphere. So, basically, a pitcher gets credit for 1 out for getting a K, about .8 for inducing a ground ball or fly ball, .98 of an out for inducing a pop-up, and only about .3 of an out for a line drive. HRs and BBs never result in an out, so they hurt a pitcher's tRA.
So basically, by using this information and adjusting to neutralize everything, we have a totally unbiased pitching metric based only on what the pitcher can control without his defense's help. So what does it tell us about the Brewers?
1 important note before reading this: tRA is expressed in Runs/9 innings. It's not directly comparable to ERA because of this. It's like using Runs allowed with errors per 9 innings instead of ERA. And there's no league adjustment. Fortunately, our friend Sky Kalkman at Beyond the Boxscore adjusted this all to get what he likes to call tERA, and put it all in a handy spreadsheet. Here's a chart of the only Brewers with a large enough sample to conclude anything:
As with most pitching metrics or advanced stats in general, tRA is going to be a bit more conservative than a traditional stat like ERA, meaning it ends up being less extreme than ERA and errs towards the average.
Sabathia, Sheets, and Bush gave up fewer actual runs than tRA would have expected in 2008. You can put it on defense, luck, or whatever, but you wouldn't expect any of the three to perform that well again.
Parra's numbers are quite close, which gives me hope for the future especially considering his BB rates were really high this year along with his WHIP. tRA shows that his ability to get strikeouts and his good stuff that induces groundballs make him a good pitcher anyway.
That leaves Suppan. tERA in this chart is comparable to ERA, so he was expected to have an ERA of 6.24 last year given neutral defense and park. Converted into runs above/below replacement by Sky Kalkman in the aforementioned spreadsheet (based on expected innings pitched, but that's for another day), Suppan was 9 runs below replacement level in 2008. Given his age and declining skills, should we really expect that to get any better in 2009 or 2010? Coupled with the fact that a replacement starter like Mark DiFelice could potentially upgrade the Brewers by a whole win in 2009, it would be wise for Doug Melvin to go into crisis management mode.
I suggested earlier that, based on his 3 VORP, it would be wise to dump Suppan even if you have to pay most of his remaining contract. Well, based on tRA, it would almost be worth more to the Brewers to pay Suppan to not pitch for them than it would be for him to pitch, assuming you accept that his skills will likely decline in the next two years.
Soup's regular tRAs in the past four years are 5.35, 6.04, 5.32, and 6.46. This is not a good trend. Hopefully the Brewers are aware of this and won't be shocked if he completely implodes in 2009.
tRA is really an interesting stat to look at. If you want something to do, go to Stat Corner and check out any player (even minor leaguers). I found out these things, remember that they're not on the ERA scale, multiply by about 90% to get an ERA comparable:
- Jeremy Jeffress posted a 3.57 tRA at Brevard County this year.
- How bad was Eric Gagne? 6.9 tRA last year.
- Just say no to Jon Garland. 5.50 and 5.74 the past two years.
- Zack Greinke posted a 3.74 tRA this year in the AL.
- As a relief pitcher, Carlos Villanueva: 3.25 in '08.
- As a relief pitcher, Seth McClung: 4.27 in '08.
- Aforementioned Mark DiFelice had a 2.33 tRA as a starter in AAA.
- Trade target J.J. Putz's trends are bad- 1.6, 2.9, 4.6 from '06-'08.
That's all I have right now. Feel free to enlighten the rest of us if you find any interesting tRA trends/numbers from Stat Corner.