The Minors in Context: Introduction

In the comments section of Friday’s article, reader Justin asked for “a description of the environments of the leagues in MiLB.” Considering the importance of contextualizing every event in the minors, even while this ground may be well-trodden, it’s territory worth returning t0. A couple weeks ago, I did a post on the different ballpark environments in the Florida State League, which will work as a framework for the rest of the series. Today, I will look at the leagues relative to each other, and, in an on-going series, slowly tackle each league more in-depth: talking about the stadiums, and divisions, that are apt to favor either a hitter or pitcher. It should serve as an important introduction to an offseason of prospect analysis.

To keep the spirit of introduction alive, let’s begin with a review of the different full-season levels of the minors, and the respective leagues at each level:

Triple-A: International League (14 teams), Pacific Coast League (16).
Double-A: Eastern League (12), Southern League (10), Texas League (8).
High-A: California League (10), Carolina League (8), Florida State League (12).
Low-A: Midwest League (16), South Atlantic League (14).

I don’t think I have to remind that each Major League team has an affiliate at every level. The league abbreviations are generally just the first letter of each word in the league (example: FSL), though the California League is CAL, the Carolina League is CAR, and the Midwest League is MWL. Sometimes, you’ll see the International League abbreviated to INT rather than IL. Moving past the really familiar, here’s a look at the average performance at each level this season — and while more years of data is always better, I would then really be piggy-backing off previous extensive work on the subject.

Level    R/G   AVG/OBP/SLG   ISO   BB%    K%    BABIP
Low-A   4.63   257/328/381   124   8.5   20.4    .314
HighA   4.62   263/332/391   128   8.2   19.8    .318
DoubA   4.55   261/334/392   131   8.9   18.8    .309
TripA   4.89   270/340/422   151   8.7   18.1    .313

There are some signs here of the developmental ladder at work. The strikeout rate goes down as players move up through the minors, with hitters seemingly improving at a higher rate than the pitchers. They are also hitting for more power, as the Isolated Power improves, too. I expected to see a gradual decrease in BABIP, to reflect an improvement in fielders, but it works as an example of why we need to get out our microscopes. As you’ll see in a second, the California League BABIP is .328, so it skews the High-A data above the Low-A. And we would see the improvement in pitchers with a decrease in runs per game if not for the Pacific Coast League (5.22 R/G) throwing off our data.

Therefore, the next logical step is to break this down by league. Let’s start with the aforementioned PCL and their Triple-A brethren, the International League.

League    R/G   AVG/OBP/SLG   ISO   BB%    K%    BABIP
PCL      5.22   277/348/432   155   8.9   17.4    .318
IL       4.51   263/330/410   147   8.4   18.8    .307

In 2010, the PCL was the best hitting environment of any professional league. The Isolated Power was higher than the California League, the strikeout rate was the lowest in the minor leagues, and the BABIP was higher than we’d expect from AAA fielders. While the International League has a low R/G mark, it also has an Isolated Power essentially equal to the Cal League. Hitters have matured, but so have pitchers, cutting down on their walk rates relative to Double-A.

Speaking of, next we move to the three Double-A leagues, which lack the huge differences that leagues in the other levels see.

League    R/G   AVG/OBP/SLG   ISO   BB%    K%    BABIP
TEX      4.48   260/334/387   127   9.1   18.4    .307
SL       4.52   263/337/390   127   9.0   19.1    .315
EL       4.63   259/332/397   138   9.8   18.8    .305

While the Texas League has the reputation of a hitters league, and played as the most hitter-friendly in AA from 2007-2009, it produced the least runs of the three leagues this year. The Eastern League, the most pitcher-friendly AA league in Inaz’ study, produced the most offense. The difference is found entirely in Isolated Power, where the EL was high. Whether this is a one-year blip, or the result of changing offense environments (read: new stadiums or organizations) will remain to be seen. The Southern League seems pretty neutral — perhaps a touch pitcher-friendly, but also had a higher BABIP than I would have thought.

Both the most- and least-friendly environments are found in High-A, with the pitcher-friendly Florida State League and hitter-friendly California League. Found in between the two is the Carolina League. Check it out:

League    R/G   AVG/OBP/SLG   ISO   BB%    K%    BABIP
FSL      4.18   255/324/364   109   8.1   20.0    .312
CAR      4.53   260/330/388   128   8.3   19.8    .314
CAL      5.21   275/344/423   148   8.4   19.6    .328

The Carolina League played more neutral than usual this year, usually leaning a little towards pitchers. The California League is simply ridiculous, with an environment easy for hitters and hard for fielders. It’s intimating confines probably explain the small rise we see in BB% relative to the other leagues, too. The Florida State League kills offense at almost the same rate the Cal League promoted it, with even a higher strikeout rate than the other leagues.

Finally, let’s check in on Low-A, with one league that I detailed on Friday.

League    R/G   AVG/OBP/SLG   ISO   BB%    K%    BABIP
SAL      4.54   256/323/377   121   7.8   20.4    .313
MWL      4.72   257/333/384   127   9.0   20.5    .315

The Midwest League has always been one of the more pitcher-friendly leagues, but this year, it was easier for hitters than the South Atlantic League. The biggest difference comes in terms of BB%, which signals to me that it might be the result of a specific talent pool rather than an ongoing trend. It’s just possible the South Atlantic League had better pitchers, or the Midwest League better hitters, then they usually do. Probably both, and we’ll talk about that when we detail their leagues.

This is where I will leave things today. We know that the Pacific Coast and California Leagues are the games most hitter-friendly. The Florida State League is the least-friendly. The International League leans towards pitchers too, as does the Southern League. The Texas League confuses me. But our answer to most questions will be answered when I break down the league’s stadiums one-by-one, which is where the series is headed next.

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Thanks, this is a very concise summary of what to expect from the various minor leagues. I have bookmarked it for future reference :-)