And Even More Refinements in SFR

As some readers will know I've been writing the last couple weeks here and on Baseball Prospectus about a play by play fielding system termed Simple Fielding Runs or SFR.

After last week's column I had a chance to tweak the system yet again, and made the following changes.

Took into consideration the additional context of whether first base was occupied for all infielders. It turns out that for first baseman on ground balls hit by lefties the percentage of runners who reach (hit or error) goes from 16% to 24% when first is occupied, and from 20% to 29% for right-handers. For second baseman in the same scenarios it goes from 27% to 29% and 30% to 34%, for shortstops, interestingly, the trend is the opposite as it goes from 34% to 30% and 32% to 31%, and for third baseman it's pretty steady at 27% to 27% and 24% to 26%. Although a smaller percentage of fielded balls, the differences are significant for bunts when there is a runner on first since the vast majority of such attempts are sacrifice bunts instead of bunt hit attempts which have a higher success rate. The end result, I'm hoping, is a higher correlation with UZR for first baseman. I have not, however, taken into consideration the ability of first baseman to catch throws from infielders.

Changed the partitioning rules for which balls are assigned to first and third baseman. In the past I was partitioning all balls in the shared areas of responsibility except for middle infielders all line drives that resulted in extra base hits. Now I also exclude bunts from the calculation as well and assign all extra base hits on ground balls to left field to the third baseman and all extra base hits on grounders to right to the first baseman on the assumption that they're hit down the line. I also no longer partition any fly balls or line drives to the outfield since by doing so we didn't seem to be adding much information to what we already knew. Finally, in the last column on the subject I noted that I used a 50/50 split on ground balls up the middle. After the article was submitted, however, I realized that there is a simple way to partition balls between the short and second area of responsibility following the same principle outlined in the column. That change has been made.

While I haven't re-run the correlations with UZR I did want to show a few results and so here are all infielders who were assigned 15 or more balls in 2007 in the National League Central. You'll notice that the range is smaller with Milwaukee's infield not looking quite so terrible as in previous versions of the system.

Team    Name                  POS   Balls     SFR
CHN     Carlos Zambrano         1      33     0.6
CHN     Jason Marquis           1      30    -0.4
CHN     Rich Hill               1      26    -1.7
CHN     Ted Lilly               1      30    -1.8
CHN     Sean Marshall           1      17    -2.3
CHN     Jason Kendall           2      17    -0.5
CHN     Michael Barrett         2      23    -0.9
CHN     Daryle Ward             3      21    -1.5
CHN     Derrek Lee              3     294    -1.8
CHN     Ryan Theriot            4     102     1.3
CHN     Ronny Cedeno            4      18     0.9
CHN     Mike Fontenot           4     200     0.1
CHN     Mark DeRosa             4     295    -0.1
CHN     Aramis Ramirez          5     406     7.1
CHN     Mark DeRosa             5     103     4.9
CHN     Cesar Izturis           6     189     2.3
CHN     Ryan Theriot            6     405     2.1
CHN     Ronny Cedeno            6      48     2.0
-------------------------------------------------
CIN     Bobby Livingston        1      17     1.4
CIN     Aaron Harang            1      25     0.8
CIN     Bronson Arroyo          1      32    -0.4
CIN     Matt Belisle            1      18    -0.9
CIN     Javier Valentin         2      21     0.0
CIN     David Ross              2      49    -0.5
CIN     Scott Hatteberg         3     167     1.2
CIN     Jeff Conine             3      91     0.1
CIN     Jorge Cantu             3      17    -0.9
CIN     Joey Votto              3      32    -1.1
CIN     Jeff Keppinger          4      16     0.3
CIN     Brandon Phillips        4     662   -10.0
CIN     Jeff Keppinger          5      34     1.8
CIN     Ryan Freel              5      52     0.5
CIN     Juan Castro             5      21    -1.5
CIN     Edwin Encarnacion       5     402   -10.5
CIN     Alex Gonzalez           6     420     2.0
CIN     Juan Castro             6      44    -0.5
CIN     Jeff Keppinger          6     184    -1.6
CIN     Pedro Lopez             6      41    -1.7
-------------------------------------------------
HOU     Chris Sampson           1      25     1.9
HOU     Roy Oswalt              1      38     1.2
HOU     Wandy Rodriguez         1      22     1.0
HOU     Woody Williams          1      40     0.2
HOU     Dave Borkowski          1      21     0.0
HOU     Brad Ausmus             2      35     0.1
HOU     Eric Munson             2      18    -0.2
HOU     Mark Loretta            3      51     2.9
HOU     Mike Lamb               3      67    -1.1
HOU     Lance Berkman           3     277    -3.5
HOU     Chris Burke             4     150     2.5
HOU     Mark Loretta            4      77    -0.3
HOU     Craig Biggio            4     398    -9.7
HOU     Ty Wigginton            5     143     1.7
HOU     Mark Loretta            5      48    -0.5
HOU     Mike Lamb               5     144    -3.5
HOU     Morgan Ensberg          5     186    -9.0
HOU     Adam Everett            6     281     9.4
HOU     Eric Bruntlett          6     180     0.3
HOU     Cody Ransom             6      35    -0.1
HOU     Mark Loretta            6     248    -2.2
-------------------------------------------------
MIL     Jeff Suppan             1      35     2.1
MIL     Chris Capuano           1      30     1.1
MIL     Dave Bush               1      26     0.4
MIL     Claudio Vargas          1      15     0.2
MIL     Johnny Estrada          2      38     0.8
MIL     Tony Graffanino         3      25     0.7
MIL     Prince Fielder          3     325    -9.7
MIL     Craig Counsell          4      84     3.0
MIL     Tony Graffanino         4      92     0.5
MIL     Rickie Weeks            4     439   -21.4
MIL     Craig Counsell          5     112     3.9
MIL     Tony Graffanino         5      74     2.2
MIL     Ryan Braun              5     309   -24.7
MIL     Craig Counsell          6      79    -0.1
MIL     J.J. Hardy              6     619    -1.7
-------------------------------------------------
PIT     Matt Morris             1      18     1.6
PIT     Ian Snell               1      20     1.6
PIT     Paul Maholm             1      35     0.8
PIT     Shawn Chacon            1      20     0.4
PIT     Tom Gorzelanny          1      28    -0.4
PIT     Zach Duke               1      23    -0.6
PIT     Ronny Paulino           2      42     0.7
PIT     Adam LaRoche            3     327     3.0
PIT     Josh Phelps             3      25     1.2
PIT     Matt Kata               4      18    -1.9
PIT     Jose Castillo           4      56    -5.7
PIT     Freddy Sanchez          4     526   -13.0
PIT     Jose Castillo           5     130     2.6
PIT     Matt Kata               5      23     0.1
PIT     Jose Bautista           5     410    -4.8
PIT     Cesar Izturis           6     107    -0.5
PIT     Jack Wilson             6     665    -0.6
PIT     Jose Castillo           6      32    -0.6
-------------------------------------------------
SLN     Adam Wainwright         1      29     1.8
SLN     Braden Looper           1      21     0.4
SLN     Joel Pineiro            1      15     0.2
SLN     Kip Wells               1      23    -0.5
SLN     Yadier Molina           2      34     0.9
SLN     Gary Bennett            2      17     0.1
SLN     Albert Pujols           3     396    10.6
SLN     Brendan Ryan            4      64     1.3
SLN     Miguel Cairo            4      19     0.6
SLN     Aaron Miles             4     242    -0.8
SLN     Adam Kennedy            4     333    -2.8
SLN     Scott Rolen             5     351    13.7
SLN     Scott Spiezio           5      68     2.4
SLN     Russell Branyan         5      28     1.6
SLN     Miguel Cairo            5      31     1.5
SLN     Brendan Ryan            5      72     0.3
SLN     Brendan Ryan            6      91     3.7
SLN     Brian Barden            6      17     1.0
SLN     David Eckstein          6     493    -7.2
SLN     Aaron Miles             6     155    -8.6