February 7, 2012 posted by Matthew Dewoskin

2012 Fantasy Baseball Stats You Should Know: FIP and xFIP Edition

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Zack Greinke, Milwaukee Brewers, Starting Pitcher

FIP and xFIP are simply a better way of analyzing what a pitcher actually controls than ERA and can actually be used as a tool to predict future success or lack thereof. Read that last sentence again and that’s the reason why fantasy GM’s should be interested in these metrics.

If you really think about it, what does ERA actually measure? Is it just the pitcher or does it depend on the defense, the batter, the umpire, the base runners, the stadium and the official scorer? Well, ERA depends an awful lot on what happens when balls are hit in play. ERA’s go down when fielders are able to catch them and up when they aren’t, but all fielders are not created equal. Anyone who has seen Ryan Theriot try to avoid injuring himself when playing the field knows that. Also the official scorer decides (apparently at random) which runs are earned and unearned. We’ve all learned how ballparks can have an impact on player performance. A long fly in Petco or Metco might be a homer in Citizen’s Bank. There are simply too many factors influencing ERA to put all of the responsibility on the pitcher.

ERA is like a live recording of a massive orchestra with a raucous crowd while FIP and xFIP are more like a studio recording of a singer and a backup band. It’s impossible to focus on just a few instruments with all the noise with the orchestra and crowd. FIP and xFIP do a great job filtering out the nonsense and focusing on what a pitcher is actually responsible for. .

FIP only uses walks, strikeouts, homers and HBP to measure what a pitcher is accountable for. These stats are based on the correct assumption that pitchers have no control over what happens once a baseball is put in play. Once the ball leaves the pitcher’s hand their role in the play is basically over unless the ball is hit back to them. FIP and xFIP are ways to calculate what a pitcher actually did without taking his defense into consideration.

Both FIP and xFIP are measured on a scale similar to ERA, so it only takes a glance to know if a pitcher has been getting by with the help of the luck dragon or if the pitcher has been unlucky and due for improvement. See a FIP or xFIP in the upper 4’s or 5’s? That’s bad. Lower 2’s? That’s where pitchers should want to be.

The only difference between FIP and xFIP is in their calculation. FIP uses the actual number of homers allowed whereas xFIP assigns a league average value(10.6% HR:FB ratio) to each pitcher. Pitcher’s home run rates have been shown to be unpredictable over time and xFIP gives an expected value rather than an actual value.

The reason Jeremy Hellickson is such a popular bust candidate is because of his FIP and xFIP numbers. Hellickson posted an anemic 5.57 K/9 and a worrisome 3.43 BB/9, but managed a sub-3.00 ERA in 2011. His FIP checked in at 4.44 and his xFIP was 4.72. Hellickson puts a lot of balls in play and unless he can improve his K rate, Hellickson owners could be in for some pain in 2012.

Zack Greinke is a trendy pre-season sleeper because of his FIP and xFIP numbers. Greinke posted a meh-inducing 3.83 ERA. In a year that was dominated by pitchers with sub-3.5 ERAs, Greinke didn’t do much for you, but he did post a 2.98 FIP and 2.56 xFIP. Both of these numbers are likely due to the fact that Greinke gets K’s in bunches(10.54 K/9) and does his best to avoid walks(2.54 BB/9). He was also a little unlucky on balls hit in the air. He owned a 13.6% HR/FB ratio which was over 4% higher than his 9.0% career average. He’s a solid bet to rebound in 2012.

It’s clear to see why the White Sox think they can win with a guy like Phil Humber, if you trust FIP and xFIP that is. Humber was pegged as a flash-in-the-pan, Quad-A pitcher who finally got lucky enough to string together a couple decent outings from the beginning of the year. Every time he went out to the mound, it felt like a piano was about to fall on him and he would give up 8 runs in ⅔ of an inning. It never really happened and if FIP and xFIP are to be trusted it likely won’t. Humber managed a 3.75 actual ERA, but posted a 3.58 FIP and 3.86 xFIP. Fantasy GM’s can basically expect more of the same as long as Humber can post a league average HR/FB rate. 


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