Saturday, January 05, 2008

Fielding Bible - 2007

This is the fifth part of my series on fielding for 2007. The Table of Contents for the series is listed below:

Basic fielding stats
Converting Zone Rating to something useful
Revised Zone Rating
Probabilistic Model of Range
Fielding Bible
Ultimate Zone Rating
Fan Fielding Survey versus range measures
Outfield arms
Ranking the second basemen
Ranking the shortstops
Ranking the third basemen
Ranking the first baseman
Ranking the center fielders
Ranking the right fielders
Ranking the left fielders
What about catchers?

Before I discuss The Fielding Bible system, I want to direct you to a database which SG has constructed over at the Replacement Level Yankees Weblog. He has put together detailed Zone Rating data from 1987-2007 including translations into runs saved above average. You can find it on the left sidebar of that site under "Fun Stuff". SG obviously put a lot of work into it and it's a valuable resource.

Now back to my analysis...

John Dewan's Fielding Bible plus/minus system has many similar features to Zone Rating (ZR), Revised Zone Rating (RZR) and especially Probabilistic Model of Range (PMR). The system is described briefly on the Fielding Bible web site. The site also has various other excerpts from their 2006 book and they are worth reading because they explain fairly complex concepts quite clearly.

On the web site, they describe how video scouts watch every play of every major league game and record information about location , distance, speed (soft/medium/hard) and type of hit (groundball, liner, flyball, bunt, fliner (somewhere between fly and liner) for each play. It's the same data collection system used for RZR and PMR but the three systems have somewhat different methods of processing the data.

In the Fielding Bible +/- system, each type play (e.g soft hit ground ball hit into the hole between short and third) has a difficulty which is determined by how many times major league fielders convert that play into an out. For example, if that play was made 30% of the time, the a player gets a score of +.70 for making that play. If he doesn't make that play, he gets a -.30. All the scores on all the plays are summed for a player to get his +/- rating. The rating represents how many plays the player made above or below those an average player at his position would make.

So +/- is equivalent to PMAA (plays made above average) which we calculated for all the other systems. As usual PMAA can then be converted to RSAA as described in Chris Dial's article. Also, PMAA and RSAA can be prorated to 150 games to get PMAA/150 and RSAA/150.

There is no Fielding Bible book this year but Baseball Info Solutions did release 2007 data for about half the players - the ten leading fielders and the five worst fielders at each position. The available results for the Tigers in 2007 are summarized in Table 1 below. You can see that the following players were among the 10 best at their positions: Jacques Jones (42 runs saved above average per 150 games), Brandon Inge (+18), Curtis Granderson (+18), and Placido Polanco (+8). Miguel Cabrera (-20) finished among the bottom five third basemen.

Table 2 compares the Tigers on ZR, RZR, PMR and +/-. It can be seen that Jones, Inge, Granderson and Polanco ranked well on all 4 systems and that Cabrera ranked poorly in each case.

Table 1: Plays Made and Runs Saved by Tigers fielders in 2007 according to +/-

Pos

player

Inn

PMAA

RSAA

PMAA/150

RSAA/150

1B

Casey

989

N/A

N/A

N/A

N/A

2B

Polanco

1,209

10

8

11

8

3B

Inge

1,310

22

18

22

18

3B

Cabrera

1,311

-24

-19

-24

-20

SS

Guillen

1,074

N/A

N/A

N/A

N/A

SS

Renteria

1,019

N/A

N/A

N/A

N/A

LF

Monroe

806

N/A

N/A

N/A

N/A

CF

Jones

645

24

20

50

42

CF

Granderson

1,285

21

18

22

18

RF

Ordonez

1,221

N/A

N/A

N/A

N/A



Table 2: Runs Saved Per 150 Games - RZR,ZR, PMR and +/-

PLAYER

RZR

ZR

PMR

+/-

Granderson

34

10

19

18

Jones

24

9

13

42

Inge

13

12

16

18

Polanco

12

4

9

8

Monroe

9

7

-12

N/A

Renteria

5

-9

-4

N/A

Ordonez

-5

10

-3

N/A

Casey

-8

8

-15

N/A

Cabrera

-13

-16

-26

-20

Guillen

-18

-7

-18

N/A

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