FIP ERA means fielding independent ERA and it is an estimated ERA based on what the pitcher controls: walks, strikeouts and HRs. See Baseball By The Numbers—Earned Run Average (ERA) and Fielding Independent Pitching (FIP) by Marilyn Green at "Redbird Rants" for more information and the formula.
I used Stathead from Baseball Reference to call up all the pitchers who had 50+ IP last year. Then I found the difference between their actual ERA and their FIP ERA.
Table 1 shows the guys who had the worst luck, that is they had the biggest negative differentials for FIP ERA - ERA.
Table 1
|
Player |
IP |
ERA |
FIP |
Diff |
|
Aaron Bummer |
58.1 |
6.79 |
3.58 |
-3.21 |
|
Shintaro Fujinami |
79 |
7.18 |
4.61 |
-2.57 |
|
Zach Davies |
82.1 |
7.00 |
4.58 |
-2.42 |
|
Hogan Harris |
63 |
7.14 |
5.02 |
-2.12 |
|
Fernando Cruz |
66 |
4.91 |
2.83 |
-2.08 |
|
Dylan Floro |
56.2 |
4.76 |
2.96 |
-1.80 |
|
Michael Grove |
69 |
6.13 |
4.36 |
-1.77 |
|
Connor Seabold |
87.1 |
7.52 |
5.75 |
-1.77 |
|
Osvaldo Bido |
50.2 |
5.86 |
4.10 |
-1.76 |
|
Josh Sborz |
52.1 |
5.50 |
3.75 |
-1.75 |
Table 2 shows the guys who had the best luck, that is they had the biggest positive differentials for FIP ERA - ERA.
Table 2
|
Player |
IP |
ERA |
FIP |
Diff |
|
Wandy Peralta |
54 |
2.83 |
5.05 |
2.22 |
|
Héctor Neris |
68.1 |
1.71 |
3.83 |
2.12 |
|
Tom Cosgrove |
51.1 |
1.75 |
3.70 |
1.95 |
|
Brusdar Graterol |
67.1 |
1.20 |
3.03 |
1.83 |
|
Kendall Graveman |
66.1 |
3.12 |
4.88 |
1.76 |
|
Dominic Leone |
54 |
4.67 |
6.29 |
1.62 |
|
Clayton Kershaw |
131.2 |
2.46 |
4.03 |
1.57 |
|
Wade Miley |
120.1 |
3.14 |
4.69 |
1.55 |
|
Bryse Wilson |
76.2 |
2.58 |
4.13 |
1.55 |
|
Ronel Blanco |
52 |
4.50 |
5.99 |
1.49 |
Bummer's differential is much greater than anyone else's. I thought that maybe he got hit hard with runners on base, but his splits don't reflect that. Did the White Sox have bad fielding? Maybe, their team FIP was 4.71 while the team ERA was 4.87. Bad, but not too bad. Certainly not close to what happened to Bummer. And if it was the fielders, we would see high numbers for his AVG & SLG allowed with runners on base, but again, that was not the case (that would not be the whole story but at least part of it). His splits can be found easily at BR.
Maybe the guys who came in after he had put some runners on just did really bad so that he got charged for the runs. I am not sure if there is an easy way to tell that.
Others have looked at the issue of what explains the difference between FIP and ERA before. I might post some of those links when I get a chance.
Update Feb. 22: Here are Bummer's AVG-OBP-SLG for his splits last year: