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Projecting Pitchers in the Minors to the Majors

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With so many Royals pitchers doing so well in the minors, I have read quite a few comparisons to some pitchers in the majors. I decided to see how some of these pitchers actually project to the majors using a formula I use to evaluate pitchers.




I have been for a while trying to figure out a good quick way to evaluate pitchers. I like the idea of FIPS and xFIPs, but I feel they still have a little too much non-pitcher controlled aspects. With FIPS, a pitcher in a small park will see more home runs than other parks. xFIPS attempts to address this by only counting the number of flyballs, not considering their distances. Another problem arises when trying to look at minor leaguers, is figuring out the league and park factors. With all that said, here is the simple formula I use to look at pitchers:

Jeff's secret pitching sauce = K/9 – BB/9 + [(Ground ball Percentage in Decimal format)*10]

I am looking at features a pitcher can control, walks and strikeouts, along with the ability to keep the ball in the ground.  All three rates used correlate well from year to year (meaning they occur consistently, with less fluctuation) for a player in a league as seen from these number from Baseball: Between the Numbers:

Winning percentage - .204
Batting average on balls in play (BABIP) - .272
ERA - .380
Home runs per batter faced - .470
Hits allowed per batter faced - .499
Walks (W) per batter faced - .676
Strikeouts (SO) per batter faced - .790
Ground ball (GB) percentage - .807


The sauce doesn't relate to any other stat, but I might adjust it to ERA at some point. It is easy, good method to figure in my head how good a pitcher pitches.


The one problem when looking at minor league numbers is that there are different K/9 and BB/9 for each league (ground ball rates are constant). I went to and reversed engineered their values from one league to the next.  I saw that the conversion values were created by Sean Smith (creator of the Chone Projection system and operates I talked to him and got permission to use the conversion values seen here:

From MLB to Lower League
League K/9 BB/9
MLB 1.00 1.00
AAA 1.10 0.72
AA 1.24 0.68
A+ 1.42 0.54


The conversion numbers are multiplied as if the player is going from MLB to the minor league and divided if going from the minors to MLB. For example if a pitcher has a K/9 rate of 10.0 in AA, he looks to have (10/1.24) = 8.1 in the majors.


Also, I needed to look at the pitcher's results from different levels and average these out. If a pitcher spent a whole season at A+ and has been ½ a season at AA, the A+ will weight twice that than the AA numbers.


Another adjustment that needs to be made is that relievers have 17% more strikeouts as a relief pitcher vice a starting pitcher.


Finally, I have run the numbers over the past 5 years on all qualified starting pitching seasons so that once the numbers for the minor leaguers has been ran, there will be someone to compare them to in the majors. Here are how the sauce values compare to each other:


Sauce Percent of Qualified Starters
>12 0.7%
11-12 6.2%
10-11 10.2%
9-10 15.6%
8-9 18.5%
7-8 22.5%
6-7 18.2%
5-6 6.4%
4-5 1.7%




Using the above methods, here is how NWRoyal's pitchers in the top 20 project to the majors.



MLB Projected

Name K/9 BB/9 GB% IP K/9 BB/9 GB% IP K/9 BB/9 GB% Score Similar Pitcher
John Lamb 6.75 1.69 26.3 5.3 10.66 1.78 46 76 7.36 3.27 44.72 8.57 A.J Burrnett 2009
Mike Montgomery 7.42 2.97 45.5 30.3 9.03 2.02 48.43 84.7 6.25 3.93 47.66 7.09 Paul Maholm 2006
Chirs Dwyer 10.19 5.09 37 17.7 9.49 3.7 41.9 73 6.98 7.02 40.94 4.05 Lowest in the majors
Dan Duffy 11.57 1.93 18.8 4.7 8.92 2.98 42.22 151.3 6.37 5.48 41.51 5.04 Daniel Cabrera 2008
Aaron Crow 6.45 4.23 60.8 125.7

5.2 6.22 60.8 5.05 Mark Redman 2006
Tim Melville

7.37 4.48 38.3 90.3 5.18 8.37 38.3 0.65 Lowest in the majors
Tim Collins 14.55 3.64 35.27 64.3 13.5 3.82 66 42 9.44 6.06 47.41 8.12 Oliver Perez 2007
  • Montgomery, Lamb and Collins look to be the only minor league pitchers projected to be major league pitchers.
  • Many of the pitchers are brought down by their walk rates.
  • Crow's Ground ball rate is insane.  Walks are really holding him back.