Positional Marginal Value Through Standard Deviation
Not all ball players are created equal. But then again, a player positioned at one defensive area has a different offensive value if he is to switch positions.

Why is the above statement true? Because these position's offensive values are radically different depending on the offensive average of each position. Historically the positions with a higher offensive average include the First Base, Third Base, Left Field, and Right Field, while positions up the middle [Catcher, Second Base, Shortstop, and Center Field] tend to be documented as being weaker.

One method for documenting positional marginal value is to first find the data for league positional average, [which I found on the Baseball Prospectus website. With the on base percentage, slugging percentage, and total plate appearances, I determine runs created percentage [which I simply multiply the on base percentage by slugging percentage].

Then I dig until I locate the individual player's stats and multiply the on base percentage by the slugging percentage and multiply this figure by plate appearances to calculate a runs created figure. Adjust runs created with the ballpark factor and divide runs created by total plate appearances. Then subtract the player's runs created average from the league average and square this figure to give us a standard deviation version of an average.

So you now have a whole series of numbers in front of you, but do not know how to read all of this. Below is an explanation how to read this set of numbers.

1. Dominent [Bonds .109561]
2. Superstar [Pujols .010609]
3. Excellent [Beltre .009025]
4. Good [Soriano .000576]
5. Above Average [Burrell .000036]
6. Marginal [Jenkins .000004]
7. Exactly Average [.000000 Roberts]
8. Below Average [Cintron -.000256]

Lastly, remember, do not compare players from different positions against each other. Simply said, the average positional data pool differs amongst each position.

2004 Positional Marginal Value [Standard Deviation]

Catcher
1) I. Rodriguez .004356
2) J. Posada .004096
3) J. Lopez .002601
4) J. Varitek .002601
5) V. Martinez .002025

First Base
1) A. Pujols .010609
2) T. Helton .009801
3) J. Thome .002809
4) M. Teixeira .002025
5) Ca. Delgado.001444

Second Base
1) M. Loretta .003136
2) J. Kent .001849
3) J. Uribe .001156
4) R. Durham .001024
5) A. Soriano .000576

Shortstop
1) Ca. Guillen .005329
2) M. Tejada .002916
3) K. Greene .001369
4) J. Rollins .001296
5) D. Jeter .001156

Third Base
1) A. Beltre .009025
2) S. Rolen .009025
3) M. Mora .006241
4) A. Ramirez .003249
5) A. Rodriguez .001764

Outfield
1) B. Bonds .109561
2) J. Edmonds .01404
3) L. Berkman .008649
4) M. Ramirez .007921
5) P. Guerrero .007744
6) J.D. Drew .007569
7) B. Abbreau .005041
8) A. Dunn .004096
9) G. Sheffield .003844
10) H. Matsui .003025
11) C. Beltran .002601
12) Er. Chavez .002209
13) A. Rowand .001600
14) M. Alou .001444
15) I. Suzuki .001296