July 31, 2003

Can Of Corn

Minor League Power

by Dayn Perry

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There's quite a bit of variance among organizations with regard to how much they value and instill patience in hitters, how much they prioritize a high on-base percentage, how open they are to drafting undersized right-handed pitchers or whether they prefer skills to tools. But every organization, regardless of their prevailing philosophical stripe, covets hitters with power. It's easy to identify power hitters at the major league level, irrespective of what measure you're using. The traditional counting stats are grossly overvalued and rife with weaknesses, but it's rather difficult to, say, hit 45 homers and somehow suck.

Tabbing power hitters in the early gestation periods is a bit more difficult. On the one hand, there was little doubt that Vladimir Guerrero and Alex Rodriguez, even as minor-leaguers, would one day be knocking the ever-loving crap out of the ball at the highest level. But what about Magglio Ordonez or Sammy Sosa, whose minor-league numbers hardly inspired hopes of greatness to come? What can we learn from today's generation of power hitters?

To begin answering this question, I've taken the top 25 active leaders in slugging percentage (as of the end of the 2002 season) and analyzed their minor league power indicators. As always, I've attempted to isolate their developmental years in the minors by excluding injury-rehab assignments. Here are the minor league cumulatives for each hitter:

Name    MLB SLG Mi SLG  Mi ISO  AB/2B   Mi XBH% AB      Rookie Age
Abreu           0.522   0.451   0.161   21.7    32.1    2,642   23
Bagwell         0.551   0.444   0.119   14.8    27.3    710     23
Bonds           0.595   0.540   0.237   17.5    40.2    402     22
Delgado         0.554   0.515   0.214   18.4    36.1    2,354   22
Edmonds         0.524   0.437   0.142   15.3    31.0    1,511   23
Garciaparra     0.562   0.466   0.179   17.9    35.5    804     23
Giambi          0.552   0.473   0.179   12.3    39.2    913     24
Giles           0.570   0.449   0.144   22.4    26.5    2,619   25
Gonzalez, J.    0.563   0.439   0.173   20.6    34.8    2,017   20
Griffey         0.562   0.576   0.256   17.1    39.9    462     19
Guerrero        0.588   0.592   0.243   13.9    38.6    1,262   21
Helton          0.613   0.488   0.162   14.0    31.9    983     24
Jones, C.       0.544   0.487   0.174   17.7    33.0    1,679   21
Klesko          0.528   0.474   0.185   18.6    34.6    1,863   23
Martinez        0.528   0.439   0.139   15.9    30.3    2,309   26
Ordonez         0.523   0.416   0.145   16.9    33.2    2,457   23
Palmeiro        0.523   0.469   0.167   15.4    33.7    1,002   22
Piazza          0.576   0.513   0.218   15.3    40.0    1,390   25
Ramirez, M.     0.599   0.595   0.279   13.6    45.9    995     21
Rodriguez, A.   0.579   0.600   0.273   16.1    42.7    645     20
Sosa            0.546   0.401   0.136   19.9    31.5    1,751   21
Thomas          0.568   0.518   0.206   14.5    37.8    593     22
Thome           0.568   0.501   0.184   18.6    32.0    1,431   22
Vaughn, M.      0.526   0.490   0.206   17.8    37.5    1,014   23
Walker          0.575   0.498   0.225   21.8    39.7    1,524   23

A brief glossary of the statistics used...

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-ats 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 eague 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 a composite of the 25 hitters...

Mi SLG   Mi ISO  AB/2B   Mi XBH%   AB      Rookie Age
0.477    0.180   17.4    34.3      1,413   22.4

Observations...

• Jeff Bagwell showed surprisingly little raw power in the minors (0.119 ISO, the lowest of any of the 25), but he did hit doubles at a decent clip.
• If you looked only at Jason Giambi's SLG and ISO, you might not see a future elite power hitter, but no player in the study hit doubles at a higher rate.
• Despite being younger than their peer groups at every stop, Manny Ramirez and A-Rod still put up some devastating power numbers in the minors.
• Bobby Abreu is a rarity among power hitters in that he had more career triples than homers in the minors.
• Only three players (Guerrero, A-Rod and Ken Griffey Jr.) posted higher SLGs in the minors than in the majors.
• Only A-Rod, Manny, Mike Piazza and Barry Bonds posted an XBH% of 40.0 or greater. An indicator of future greatness?
• Only nine of 25 hitters (36 percent) posted a minor-league SLG of at least .500.

Some interesting numbers here. But to etch them in sharper relief, we'll need to compare them to hitters who, despite some impressive minor-league power numbers, failed to wield those skills at the highest level. A good topic for next week.