August 14, 2003

Can Of Corn

Minor League Power, Part III

by Dayn Perry

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In 1992, Jon Bon Jovi crooned:

"With an ironclad fist, I wake up and French kiss the morning."

Put this lyric alongside Rilke's "Archaic Torso of Apollo" or Goya's "Black Paintings" as one of the most haunting creations in the history of the Western artistic canon. What does this have to do with the third part of our series on projecting power at the major league level? Enough to include it.

You'll recall that for the last two weeks we've looked at the divergent paths, in terms of power, of two distinct groups of minor-league hitters. The first, deftly named Group A, comprised the top 25 active leaders in slugging percentage who had at least 3,000 major league ABs as of the end of the 2002 season. Group B consisted of hitters who, despite putting up strong minor league power numbers, failed to bust out the lumber at the highest level. To populate Group B, I included anyone with a career minor league SLG of at least 0.490, at least a 10% decline in their SLG in the majors and at least 1,750 ABs in the majors.

And once again, here's a brief glossary of the statistics used in this the first two parts of the study:

MLB SLG - The hitter's slugging percentage at the major league level.

Mi SLG - The hitter's minor league slugging percentage.

Mi ISO - The hitter's minor league isolated slugging percentage, which is simply SLG minus batting average. A minor league ISO of around 0.200 or greater generally indicates a high level of raw power.

Mi AB/2B - The hitter's minor league ratio of at-bats to doubles. Put another way, it's the average number of at-bats between doubles for that particular hitter. It's been theorized that hitters in the minors who hit a lot of doubles will develop additional home run power as they mature.

Mi XBH% - The hitter's minor league extra-base hits expressed as a percentage of total hits.

Rookie Age - The age at which the hitter reached the majors, more or less, to stay.

And here's how the two groups compared on an aggregate level:

Group   Mi SLG  Mi ISO  Mi AB/2B        Mi XBH% AB      Rook. Age
A       0.477   0.180   17.4    34.3    1,413   22.4
B       0.526   0.215   15.1    37.9    1,265   22.7

I chose those in Group B specifically for their high minor league SLGs, so it's neither surprising nor interesting that they would outslug those in Group A. What might inspire a spit-take is the fact that they also bested Group A in every peripheral power indicator. So what gives?

Maybe it's command of the strike zone that forecasts power better than actual power indicators. Sounds counterintuitive, but, hell, I'm running out of ideas. So to test this theory, we'll look at the following measures:

UBB% - Minor league unintentional walks expressed as a percentage of at-bats.

UBB/K - Ratio of minor league unintentional walks to strikeouts.

CT% - Contact rate. The percentage of hitter's minor league at-bats that didn't end in a strikeout.

Now let's all welcome back the denizens of Group A:

                UBB%    UBB/K   CT%
Abreu           13.1    0.58    78.7
Bagwell         12.3    1.06    88.4
Bonds           17.4    0.84    79.4
Delgado         14.1    0.63    77.6
Edmonds         11.7    0.42    72.0
Garciaparra     8.8     1.01    91.3
Giambi          16.6    1.07    84.4
Giles           13.3    1.08    87.6
Gonzalez, J.    6.4     0.31    79.2
Griffey         16.1    0.80    79.8
Guerrero        8.6     0.81    89.4
Helton          14.0    0.93    84.8
Jones, C.       10.1    0.74    86.2
Klesko          11.2    0.69    83.6
Martinez        18.6    1.69    89.0
Ordonez         7.9     0.53    85.1
Palmeiro        9.1     1.03    91.2
Piazza          8.1     0.41    80.1
Ramirez, M.     14.2    0.64    77.9
Rodriguez, A.   8.7     0.44    80.3
Sosa            6.8     0.31    78.3
Thomas          25.6    1.38    81.5
Thome           15.0    0.70    78.8
Vaughn, M.      13.2    0.63    79.0
Walker, L.      12.2    0.46    73.1

Show some love for Group B once more:

                UBB%    UBB/K   CT%
Beltre, A.      14.3    0.91    84.2
Biggio, C.      15.7    1.08    85.5
Burrell, P.     18.9    0.81    76.7
Casey, S.       9.3     0.73    87.3
Erstad, D.      9.8     0.62    84.2
Grace, M.       10.5    1.84    94.3
Guillen, J.     5.2     0.30    82.8
Johnson, C.     13.4    0.60    77.5
Kapler, G.      10.9    0.73    85.1
Karros, E.      10.6    0.66    83.8
Konerko, P.     12.9    0.78    83.3
Lee, T.         14.8    0.82    81.9
Ramirez, A.     14.2    0.86    83.4
Walker, T.      11.9    0.75    84.1
Zeile, T.       13.4    0.77    82.7

And the cumulative comparisons:

Group   UBB%    UBB/K   CT%
A       12.0    0.67    82.2
B       12.0    0.74    83.9

So much for that idea. Group B shows a better command of the strike zone in all three areas (they have a negligibly higher walk rate). No, the real culprit may in fact be park effects. Group B logged 29.7% of its at-bats in the generally hitter-friendly haunts of the California and Pacific Coast Leagues. In contrast, Group A spent only 15.2% of its ABs within those particular circuits. That's a huge difference, and it's a reminder that park tendencies, particularly at the minor league level, are ignored only at the peril of the analyst or organization.