Jason Hammel and the Oddity of ERA

ERA can be a weird thing at times. I love it, but it doesn’t always reveal the full story. Jason Hammel is the perfect subject. After six years in the Rays minor league system, and three bad stints with the Rays Major League club, he found himself looking up at a logjam of starting pitchers in Tampa Bay. The Rays traded him to the Rockies after the 2008 season in exchange for Aneury Rodriguez.

With the trade to Colorado, Hammel was given a great opportunity to start in the Majors for a full season. Since his arrival in Colorado two seasons ago, Hammel has been nothing but consistent. Take a look at his stats:

Stat 2009 2010
IP 176.2 177.2
FIP 3.71 3.70
xFIP 3.81 3.81
BABIP .337 .337
K/BB 3.17 3.00
HR/9 0.87 0.91
AVG .290 .286
LOB% 69.5% 68.6%
WHIP 1.39 1.40
GB% 46.2% 46.7%
fWAR 3.8 3.7
rWAR 1.8 1.7
Batters Faced 770 771
W-L 10-8 10-9

The model of consistency. The odd thing about his numbers, though, is that his ERA has been different each year, and by almost half a run. In 2009, his ERA was 4.33 with an ERA+ of 109. In 2010, his ERA was 4.81 with an ERA+ of 96. With matching FIP and xFIP, and just about every other stat known to man, you would think his ERA would’ve been the same, or close to it, but that’s not the case. His ERA+ tells us that he was above averge in 2009 and below average in 2010. Was he really above league average in 2009 and below league average in 2010? I lean towards no.

So, why was his ERA half a run worse in 2010 than in 2009 while only facing one more batter? I can only find one explanation: Errors.

In 2009, Hammel allowed 94 runs, and in 2010 he allowed 97 runs, keeping with his consistent efforts. In 2009, he allowed 85 earned runs, and in 2010 he allowed 95 earned runs. Over 177 innings, 10 earned runs equals almost exactly half a run.

So, what type of ERA can we expect out of Hammel is 2011? Do we punish him for his fielders’ errors? No, we award him with his peripherals. I’ll lean towards an ERA closer to his 2009 season than his 2010 season, but with ERA being the odd thing it is, Hammel could post the exact seasons he had in 2009 and 2010 and still post a third different ERA. This does not mean that ERA is a bad stat — in fact, I really like it — but it means that we have to look past ERA because, like I said, it rarely tells the entire story.

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13 Responses to “Jason Hammel and the Oddity of ERA”

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  1. JayT says:

    It seems to me (without looking at any stats at all) that 2 unearned runs is a lot closer to what Hammel can expect going forward rather then 9 unearned runs.

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  2. Agreed that the 2 unearned runs is closer but with his FIP and xFIP we should still see a dip in his ERA closer to his 2009 numbers.

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  3. frank pepe says:

    great stuff.

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  4. Matt says:

    “Do we punish him for his fielders’ errors? No, we award him with his peripherals.”

    How was he ever punished for his fielders’ errors? In 2009 a higher percentage of the runs he allowed were deemed not his fault, due to errors, resulting in a lower ERA.

    Had those fielders not made those errors, his ERA wouldn’t have changed much, if at all. What would definitely change is the number of total runs allowed and batters faced. So really, those particular numbers of his in 2009 and 2010 don’t show consistency in Jason Hammel, they show inconsistency in his defense (provided of course that errors are being consistently attributed).

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  5. Thanks Frank.

    Matt, you’re missing the point. What I meant by punish him is suggesting that there will only be two errors and hurt his ERA or be 10 errors and help his ERA is blind faith in ERA. Errors are part of the game and you can’t use ERA as the defining stat for a pitcher’s worth. His fielders are making his ERA the only thing that is inconsistent, not him. All of his rates are almost exact from one season to the next, making him consistent. Looking at his peripherals gives us a better chance at predicting his future outcome than ERA because it, unlike Hammel, is inconsistent.

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  6. Bryz says:

    Those similar seasons for Hammel remind me of Nick Blackburn’s 2008 and 2009. However, Blackburn was able to post similar ERAs (4.05 and 4.03) those two years.

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  7. Good call Bryz. I didn’t realize Blackburn had two seasons that close. Hammel’s is definitley the most mirrored back-to-back seasons I’ve seen.

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  8. Kincaid says:

    Those match between those two lines is pretty remarkable. Excellent find there.

    About 92% of runs are unearned, so 9 unearned runs would be closer to normal for Hammel’s line than 2.

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  9. I actually wrote about precisely the same thing a couple months ago. http://tinyurl.com/4crht8f.

    My conclusion was that he just gave up his hits in bunches a little more often, resulting in bigger innings, rather than splitting up the multitude of hits he gave up across innings.

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  10. Good read Andrew. Sorry if it looks like I duplicated your post, I had no idea there was a similar article out there. Great minds think alike. =)

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  11. a D u B says:

    Hey Jonathan,

    I was really glad to see this article, because I had just asked this exact question to Rob Neyer in his latest MLB Chat. I didn’t get much of an answer, so I’m glad you fully elaborated. I’m curious if my question sparked you to write this article? Insane how similar those peripherals are!

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  12. Glad you liked it. I miss most of Neyer’s chats and haven’t been a part of one since last summer.

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  13. a D u B says:

    Not missing much to be honest. He’s gradually getting lower and lower on my list.

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