Those who mingle within the saber community know there are a few rules to abide by, particularly when talking about pitching. Pitcher wins are not to be spoken of, ever. ERA is an important statistic, but should be considered lightly. And instead of saying acronyms like E-R-A, words such as FIP or xFIP are used.
A topic of conversation that is sure to draw some attention at a saber party is Danny Duffy's recent success in Kansas City. The 25-year-old has been dominant in June with a 2-2 record and 1.71 ERA. Two years removed from Tommy John surgery, he is blossoming into a promising piece of the Royals future. After a strong June, Duffy is now 4-7 overall with a 2.69 ERA on the season. The win total is not great, but his ERA is quite low.
I got caught in the trap! I am talking about pitcher wins and ERA without context! How will I ever fit in with my saber buddies!?
Joking aside, Danny Duffy presents an interesting case when considering pitcher wins and ERA in evaluating a young pitcher without a lot of history to rely on. Playing for the Royals, he is on a competitive team who has scored at least three runs for him in four of his ten starts, and at least six runs in three of those starts. But on average he is getting the least amount of run support of any Kansas City starter, hence his 4-7 record. Of course, we can qualify his record by looking at his low ERA, but even that might not tell the whole story. His FIP, yes, that funny sounding word that really means fielding independent pitching, suggests that his ERA is lower than perhaps it should be. Duffy is a bit of an enigma, to use a funny sounding word that everyone can understand.
Fielding independent pitching measures the things that are theoretically within the pitcher's control. Walks, hit batters, strikeouts, and home runs are outcomes that the defense playing behind the pitcher cannot affect. Beyond quality of defense, whether a ground ball sneaks past the infield or goes straight to a fielder's glove is partially luck, too. So FIP attempts to put a value on a pitcher based on the things that they can control. Danny Duffy's FIP is 3.86, or about one run higher than his ERA. If we use xFIP, which is FIP but adjusting for league average home run to fly ball rates, the number climbs to 4.55, or not very good.
We can see from the chart above some of the statistics that make up FIP, as well as a few others that help make friends at saber parties. Duffy has a K/9 rate that is decent, but not great at 6.93. His walk rate has been a troublesome part of his development, and remains high at 3.39. He is preventing home runs, which is good. But he is definitely benefiting on the lack of balls in play falling for hits.
As anyone who watches baseball knows, a hard hit ball can be caught just as easily as a softly hit ball can find open grass. It's not always the pitcher's fault so we use BABIP, which has a league average of .294, to see which pitchers are more lucky than others. Duffy is fortunate at .217 BABIP.
And speaking of balls in play, ground ball percentage is another key number to consider as ground balls are generally preferred to allowing fly balls that can turn into extra base hits or line drives that have the highest chance of turning into a hit of any kind. Duffy's GB% of 33.4 could be higher.
It isn't a saber party if sample sizes aren't discussed over appetizers. Danny Duffy has made ten starts this year, and it is clear that he is finding his groove of late. The question, as Dave Cameron asked on his most recent podcast, is how much weight do we put on recent data. Do we trust what Duffy has shown us in his last few starts as a sign that he has turned the corner? Or do we trust a broader sample of data used to make projections on his performance?
ZIPS projects Duffy to pitch to a 4.16 ERA and 4.01 FIP through the rest of the season. The history of control problems that he has experienced at every level throughout his career is too hard to overlook. And we can't expect his .217 BABIP to stay so low either. The projections are logical.
Royals fans should be excited about Danny Duffy. It is the saber parties who worry whether his recent success is a sign of better things to come or not. But more than anything, Duffy presents an interesting case on how pitching wins and ERA can tell different stories, even when digging into the advanced numbers. Nobody thinks Duffy has pitched worthy of a losing record, but perhaps his 2.69 ERA is a bit misleading as well.
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Jeffrey Bellone is an editor and featured writer at Beyond The Box Score. He can also be found writing for the saber-slanted site Inside the 'Zona, and about the Mets at Amazin' Avenue and Mets Merized Online. He writes about New York sports at Over the Whitestone. You can follow and interact with him on Twitter @JeffreyBellone.