Because the standard roto format uses batting average, most analysis, rankings, and projections are based on that and the other standard roto categories. If your league uses additional categories or replaces traditional categories with new ones like average being replaced by OBP, you’re can’t just rely on the normal analysis and cheat sheets provided by fantasy sites. You’re going to have to do a little bit of extra work. The purpose of this post is to aid those playing in leagues in which OBP has replaced average as a category.
When OBP replaces average, you can’t simply look at the guys who have the best OBPs to determine who gains an advantage in this format. What really matters is the difference between OBP and average. To determine when the difference becomes significant, I created a spreadsheet with all qualified hitters from the last three years with their OBP and average. Then I calculated the difference between those numbers, the mean and the standard deviation for the differences. The mean was .068 and the standard deviation was .02. I then sorted the differences large to small and cut out all players that were within one standard deviation of the mean. Below are the lists of players who were more than one standard deviation from the mean.
Name  AVG  OBP  Difference 
Two Standard Deviations or More Above the Mean 

Carlos Pena  0.206  0.337  0.131 
Jose Bautista  0.271  0.4  0.129 
Daric Barton  0.249  0.369  0.12 
Adam Dunn  0.212  0.33  0.118 
Prince Fielder  0.291  0.409  0.118 
Lance Berkman  0.275  0.391  0.116 
Carlos Santana  0.247  0.363  0.116 
Joey Votto  0.321  0.434  0.113 
Mark Reynolds  0.213  0.326  0.113 
One Standard Deviation or More Above the Mean 

Kevin Youkilis  0.264  0.372  0.108 
Josh Willingham  0.257  0.361  0.104 
John Jaso  0.256  0.36  0.104 
Chase Utley  0.264  0.367  0.103 
Ben Zobrist  0.259  0.359  0.1 
Alex Avila  0.26  0.358  0.098 
Carlos Quentin  0.251  0.349  0.098 
Todd Helton  0.27  0.366  0.096 
Brett Gardner  0.269  0.365  0.096 
Travis Hafner  0.267  0.363  0.096 
David Ortiz  0.296  0.391  0.095 
Dan Uggla  0.248  0.343  0.095 
Russell Martin  0.231  0.326  0.095 
Mark Teixeira  0.252  0.347  0.095 
ShinSoo Choo  0.284  0.378  0.094 
Jayson Werth  0.271  0.365  0.094 
Mike Napoli  0.261  0.355  0.094 
Rickie Weeks  0.255  0.349  0.094 
Dexter Fowler  0.275  0.367  0.092 
Nick Swisher  0.274  0.366  0.092 
Jonny Gomes  0.249  0.34  0.091 
Geovany Soto  0.234  0.325  0.091 
Jason Heyward  0.261  0.352  0.091 
Matt Joyce  0.256  0.347  0.091 
Curtis Granderson  0.247  0.337  0.09 
Evan Longoria  0.275  0.365  0.09 
Logan Morrison  0.25  0.339  0.089 
Chipper Jones  0.276  0.365  0.089 
Chris Young  0.243  0.331  0.088 
Name  AVG  OBP  Difference 
One Standard Deviation or More Below the Mean 

Jonathan Lucroy  0.279  0.326  0.047 
Ronny Cedeno  0.254  0.301  0.047 
Vernon Wells  0.244  0.291  0.047 
Jeff Keppinger  0.296  0.341  0.045 
Melky Cabrera  0.303  0.348  0.045 
J.J. Hardy  0.256  0.3  0.044 
Erick Aybar  0.274  0.317  0.043 
Mark Trumbo  0.259  0.302  0.043 
Michael Young  0.299  0.341  0.042 
Adam Jones  0.284  0.326  0.042 
Daniel Murphy  0.302  0.344  0.042 
Ian Desmond  0.271  0.313  0.042 
Darwin Barney  0.263  0.305  0.042 
Alcides Escobar  0.262  0.304  0.042 
Howie Kendrick  0.284  0.325  0.041 
Carl Crawford  0.283  0.324  0.041 
Ben Revere  0.278  0.319  0.041 
Rajai Davis  0.263  0.304  0.041 
Alex Rios  0.273  0.313  0.04 
Danny Valencia  0.257  0.297  0.04 
Starlin Castro  0.297  0.336  0.039 
Adrian Beltre  0.314  0.353  0.039 
Chris Johnson  0.279  0.318  0.039 
Miguel Tejada  0.259  0.298  0.039 
A.J. Pierzynski  0.278  0.316  0.038 
Alexei Ramirez  0.272  0.31  0.038 
Alex Gonzalez  0.247  0.285  0.038 
Vladimir Guerrero  0.295  0.332  0.037 
Ichiro Suzuki  0.29  0.326  0.036 
Orlando Cabrera  0.251  0.286  0.035 
Omar Infante  0.289  0.323  0.034 
Delmon Young  0.278  0.311  0.033 
Miguel Olivo  0.239  0.271  0.032 
Mike Aviles  0.27  0.302  0.032 
Jose Lopez  0.236  0.265  0.029 
Two Standard Deviations or More Below the Mean 

Yuniesky Betancourt  0.251  0.275  0.024 
As you can see on the “good” list, there are a lot of high profile hitters with great OBPs not listed. Guys like Adrian Gonzalez, Buster Posey, Ryan Braun and many others aren’t on the “good” list because they already have good batting averages and thus don’t get a bump in an OBP format.
As mentioned, most rankings and analysis are based on the assumption of batting average as a category. My own personal rankings and projections are as well because that’s the format that I, and most readers, play in. For my projection system I use something I call roto rating. The idea is fairly straightforward. I project all hitters in each of the five standard roto categories and then I assign them a value for each category on a scale of 110. The scale is created by creating ten tiers for each category.
I took the 200 hitters from last year with the most plate appearances (this being roughly the number of hitters usually drafted in a standard 12team league) and created the tiers based on that list. For example, there were 20 hitters who had a batting average above .307 last year and the next 20 hit between .292 and .306. If I projected a guy to hit .307 or better, I assigned him ten points for average. If I projected a guy to hit between .293 and .306, I assigned him nine points. And so on and so forth. After I did that for each category, I added up all the points and gave each guy a roto rating (You can see my top 200 here).
To determine how much of a bump to give or how much to knock a hitter down in an OBP league, I created tiers for OBP. Below are the tiers I used for average and OBP.
Pts 
OBP 
Pts 
AVG 

10  .370 or higher  10  .307 or higher  
9  .361.369  9  .293.306  
8  .349.360  8  .286.292  
7  .341.348  7  .275.285  
6  .334.340  6  .270.274  
5  .327.333  5  .260.269  
4  .322.326  4  .250.259  
3  .313.321  3  .241.249  
2  .303.312  2  .229.240  
1  .302 or lower  1  .229 or lower 
From there I could compare where a guy fell in the average tiers to where he fell in the OBP tiers and adjust my rankings accordingly. Below are the guys listed previously, this time with the number of points they would have gained or lost in my “roto rating” system.
Name 
Points Change 
Name 
Points Change 

Jose Bautista 
6 
Delmon Young 
5 

Daric Barton 
6 
Mike Aviles 
5 

Carlos Santana 
6 
Ben Revere 
4 

Josh Willingham 
5 
Chris Johnson 
4 

Lance Berkman 
5 
A.J. Pierzynski 
4 

Kevin Youkilis 
5 
Alexei Ramirez 
4 

Joey Votto 
4 
Ichiro Suzuki 
4 

Adam Dunn 
4 
Vladimir Guerrero 
4 

Carlos Pena 
4 
Omar Infante 
4 

Prince Fielder 
4 
Yuniesky Betancourt 
4 

John Jaso 
4 
Jonathan Lucroy 
3 

Chase Utley 
4 
Mark Trumbo 
3 

Ben Zobrist 
4 
Erick Aybar 
3 

Carlos Quentin 
4 
Adam Jones 
3 

Brett Gardner 
4 
Ronny Cedeno 
3 

Travis Hafner 
4 
J.J. Hardy 
3 

Dan Uggla 
4 
Ian Desmond 
3 

Mark Reynolds 
3 
Darwin Barney 
3 

Rickie Weeks 
3 
Alcides Escobar 
3 

Matt Joyce 
3 
Carl Crawford 
3 

Alex Avila 
3 
Rajai Davis 
3 

David Ortiz 
3 
Alex Rios 
3 

ShinSoo Choo 
3 
Starlin Castro 
3 

Jonny Gomes 
3 
Howie Kendrick 
3 

Todd Helton 
3 
Danny Valencia 
3 

Mark Teixeira 
3 
Miguel Tejada 
3 

Jayson Werth 
3 
Orlando Cabrera 
3 

Mike Napoli 
3 
Jose Lopez 
3 

Nick Swisher 
3 
Vernon Wells 
2 

Jason Heyward 
3 
Jeff Keppinger 
2 

Curtis Granderson 
3 
Daniel Murphy 
2 

Chris Young 
3 
Melky Cabrera 
2 

Russell Martin 
2 
Michael Young 
2 

Evan Longoria 
2 
Alex Gonzalez 
2 

Dexter Fowler 
2 
Miguel Olivo 
2 

Geovany Soto 
2 
Adrian Beltre 
2 

Logan Morrison 
2 

Chipper Jones 
2 
Just to give this a little perspective, any player going after the first few rounds would go up or down about a round for each two points gained or lost. For the guys going in the first two rounds, the changes in value are a little smaller. On the good side of things, Jason Heyward probably becomes a nodoubt second round pick if he wasn’t already there for you, Prince Fielder and Jose Bautista become surefire first rounders, and Joey Votto is the clear #4 pick behind the big three and might even be worth drafting ahead of some of the big three depending on how high you were on Votto to being with. When I calculated the mean and standard deviation for OBP, Votto’s OBP came in at more than four standard deviations above the mean. On the “bad” side of things, Adam Jones goes from a late third/early fourth option to a late fourth/early fifth option, Adrian Beltre goes from a late second/early third to a fourth rounder, and Starlin Castro goes from a fourth to a late fifth or sixth rounder.