Chronicles of the Lads

PROBABILISTIC RUNS?
David Pinto has published his defensive ratings of shortstops for 2004.

It occurred to me that it might be possible to convert these results into an estimate of how many runs against average each SS prevented.

To do this, I turned to Chris Dial's methodology, in which a run value is assigned to each out a defender makes. For instance, 98.7% of outs made by a SS prevent a single. A single is worth .47 runs. Each out is also just that: an out, which has a value of roughly .28 runs. So, 98.7% of the outs made by a SS prevent .75 runs. (The other 1.3% account for 1.06 runs each, because sometimes those screamers by the SS get through the gap and go to wall for extra bases.)

So, in looking at Pinto's methods, we can easily see how many outs each shortstop made against expected, which is different from average. What I did here was go through and convert those outs to runs. For all the SS's he lists, the mean Runs Against Expectation was -16.22 per 4000 balls in play (roughly the amount a full-time SS would see, maybe a bit lower). So we can compare each individual's outs per 4000 BIP against -16.22 to see how far above average they were in 2004.

For instance, David Eckstein had 3,562 balls in play against him. He made outs on 356 of these when about 400 would have been expected, based on the probabilities observed from 2002 through 2004. Using Dial's methodology, we find that he prevented 268.43 runs where 301.81 would have been expected; so he's -33.37 Runs Against Expected. We convert that to 4,000 BIP to get a number of -37.47. However, as the average SS was -16.22, that makes Eck -21.26 against average, which is pretty bad -- and quite honestly, that surprised me a great deal.

Anyway, here's the above method applied to everyone Pinto has listed for 2004:

Player          Runs Above Average per 4000 BIP

Pokey Reese         26.5559

Adam Everett        23.1330

Cristian Guzman     21.2978

Julio Lugo          18.4622

Rich Aurilia        17.2691

Bobby Crosby        15.7747

Jose C Lopez        14.2525

Jimmy Rollins       13.6555

Alex Gonzalez       13.4198

Neifi Perez         13.0626

Cesar Izturis       11.8924

Chris Woodward      11.1344

Carlos Guillen      10.8787

Chris Gomez         10.7692

Wilson Delgado      3.70296

Orlando Cabrera     3.11573

Khalil Greene       2.47566

Craig Counsell      1.89519

Jose Valentin       1.26903

Jack Wilson        -1.09913

Ramon E Martinez   -1.65256

Edgar Renteria     -3.28747

Derek Jeter        -4.39761

Jose Vizcaino      -6.43863

Miguel Tejada      -8.44408

Royce Clayton      -8.98143

Michael Young      -9.35026

Kazuo Matsui       -9.70417

Deivi Cruz         -11.4588

Omar Vizquel       -12.7924

Alex Cintron       -12.7784

Angel Berroa       -14.8513

Alex S Gonzalez    -15.6186

Barry Larkin       -17.3740

Rafael Furcal      -19.6530

David Eckstein     -21.2571

Nomar Garciaparra  -23.4721

Felipe Lopez       -36.9916