If you're a regular reader of "Here's a Thought," you probably know that I don't like to use ERA very much.
Instead, I prefer FIP, tRA, and xFIP when discussing pitchers. The statistics are just luck-adjusted ERAs, so they slot in nicely to ERA's "traditional" statistical role.
Thus, an easy way to tell how "lucky" a pitcher is is to look at the ERA-FIP difference. Fangraphs has a handy leaderboard of this difference, so I decided, for fun, to take a look at 2009's pitchers with at least 50 innings and see who was the "luckiest:" that is, whose ERA was the lowest compared to his FIP.
The winner, with a 3.32 ERA and 5.32 FIP, is Astros lefty reliever Tim Byrdak, with an even two-run difference.
Byrdak is pretty much your standard situational lefty, throwing a high-80's fastball and a ton of low-80's sliders.
So, what makes his FIP bad?
Simply put, Byrdak has terrible control. His career MLB walk rate is 5.68 BB/9, and he walked 36 batters in 61.3 IP this year (5.28 BB/9). Only 44% of his pitches found the strike zone, compared to the 49.3% league average, in 2009.
Making things worse, Byrdak served up 10 long balls on the season (1.47 HR/9). That's not surprising with such poor control; after he falls behind in counts, Byrdak has to throw get-me-over pitches which can get crushed.
While he's got a great slider and changeup, Byrdak's fastball, which he throws about half the time, was one of the worst in the majors last year, at -1.86 runs per 100 pitches according to Pitch Type Linear Weights.
And what made his ERA good?
A .201 BABIP and 85.9% strand rate will do stuff like this for a pitcher. Byrdak's career BABIP is .290 and his strand rate is 75.2% (and that includes 2009's wacky totals), so it's not like he's long had some ability to defy the baseball gods (although, strangely, his FIP was 1.56 runs higher than his ERA in 2008. We'll get to that in a bit).
To his credit, Byrdak's slider and change had great success in 2009, and he struck out 8.51 batters per nine innings, a nice total.
Undoubtedly, Byrdak was lucky in 2009. But was he the luckiest pitcher in baseball?
Probably not, actually. The BABIP can actually be somewhat explained by Byrdak's line-drive rate, a stunningly low 13.7%.
His homer rate was also a bit fluky (and probably influenced by the fact that righties, who Byrdak struggles with, have a short porch to face in Houston), as his HR/FB rate was 13.9%, higher than normal. His career rate is 12.6%.
If he were in a neutral park, Byrdak's homer rate would probably be about average, and his extraordinary job at preventing liners in 2009 means his BABIP should only have been around .260 (but that's still much higher than .201.
We see the reflection of these additional pieces of data in Byrdak's xFIP (which normalizes HR/FB rate) and tRA (which accounts for batted-ball splits).
Byrdak's xFIP lops .51 runs of his FIP, at 4.72. His tRA takes off another .43, at 4.80.
Byrdak may actually have deserved to allow .94 runs less than his FIP says, which would put his true "ERA" at 4.29.
While Byrdak benefited from some luck in 2009, he actually wasn't the luckiest pitcher in baseball.
ERA paints one picture. FIP paints another one. The truth often can lie somewhere in between.
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