After we speculated about it in May, Astros owner Jim Crane announced on June 29 that he was looking to relocate the Astros' High-A affiliate - currently the Lancaster Jethawks in the California League - to a to-be-named Carolina League team in Fayetteville, North Carolina.
Lancaster, home to the Astros' High-A team since the 2009 season, has a reputation as an extreme hitters' park. A combination of altitude, aridity, and fierce winds that usually blow out to right field all adds up to offense, and a lot of it. Because of that, there has been some speculation - including by yours truly - that when hitters are knocking every other ball over the fence, it may be hard to teach them good habits, like pitch selection, that will make them more-effective professionals in the long run.
Crane mentioned that the team was looking to move its affiliate to North Carolina for "efficiency reasons and developmental reasons." Could those developmental reasons be related to the extreme environment? I decided to take a closer look.
First, I compiled a list of players who played in High-A ball between 2009 and 2013 (to give them time to "age up" into the major leagues.) From there, I isolated the players who had played their High-A ball in extreme offensive (positive), extreme defensive (negative), and neutral parks. I ran three-year park splits wherever possible (in other words, when an individual park had been around for at least three years,) and each season I broke off the five highest-offensive parks (in terms of home runs) and the five lowest-offensive parks.
First, a look at their raw statistics in High-A ball:
K% BB% ISO BABIP wOBA wRC+ Positive 19.71% 8.61% .157 .331 .349 105 Neutral 19.19% 8.69% .134 .318 .337 104 Negative 18.84% 8.63% .120 .313 .330 103
Nothing terribly surprising here. As expected, hitters in positive environments have higher ISOs, BABIPs, wOBAs, and wRC+ rates, but they also strike out more. Hitters from neutral environments tend to walk more than those from both positive and negative environments, but they're all pretty close to equal in that regard.
What I then wanted to see was how these players did in the majors. In other words: If hitters are learning bad habits in High-A, are those problems preventing them from becoming good major league hitters? If so, then it's problematic. If not, then at best, it's interesting.
So I looked at the major league stats of players who had played their High-A ball in positive, neutral, and negative environments:
K% BB% ISO BABIP wOBA wRC+ Positive 23.49% 7.52% .135 .303 .300 87 Neutral 22.40% 7.02% .131 .294 .294 83 Negative 21.70% 6.92% .140 .299 .303 90
Some of these numbers back up exactly what you would expect: Hitters who came from offense-friendly environments strike out a lot more than those who come from pitcher parks, for instance. Hitters from those pitchers' parks tend to have more power, which may owe itself partially to the fact that they had to work harder in High-A to hit the ball out, thus encouraging them to refine their approach earlier.
But, then, how to explain the higher walk rate for the players from positive parks? Sure, maybe they're showing better selection skills because they're trained to know that they'll eventually get a pitch to clobber. But these are players three levels removed from High-A. It's hard to imagine there would be that significant an impact in their major league numbers.
When you really start to look at this chart and to try to create storylines out of it, in fact, the more it really just looks like noise.
There are a few reasons for this: First is because the sample of players who played in High-A during my time period, who have gone on to the majors, is relatively small. Second, and I think this is most-important, is because this is already a fairly self-selective process. The players who make it to the majors have, at least to some degree, fixed whatever problems they encountered in High-A ball. If anything, one might look to the attrition rates between High-A and the majors to see how many prospects flame out, rather than to look at the MLB statistics and to try and draw anything meaningful out of them.
My solution to this problem wasn't perfect, but I feel pretty good about it: I looked at how players did in Double-A after spending time in positive, neutral, and negative run environments in High-A.
K% BB% ISO BABIP wOBA wRC+ Positive 19.06% 9.17% .138 .319 .342 109 Neutral 18.58% 9.01% .142 .318 .344 110 Negative 18.62% 9.00% .141 .315 .342 110
Players in neutral and negative environments look very similar in this chart, and players from positive environments begin to look like real outliers: They walk and strike out more, and they hit for less power. But their overall offensive ability, measured by wRC+, is pretty much in-line with those from other environments.
The differences really begin to manifest themselves, however, as we move into looking at Triple-A numbers. Keeping in mind that, as before, the samples become less reliable the further we get from High-A, this begins to look like a pattern that at least makes sense:
K% BB% ISO BABIP wOBA wRC+ Positive 52.17% 9.12% .149 .326 .345 104 Neutral 52.38% 8.99% .157 .331 .354 113 Negative 51.17% 8.44% .148 .326 .347 111
Here, most of the peripherals have begun to stabilize (way to go, minor league instructors!), but despite that, the overall hitting ability of positive-environment players really seems to lag behind, at 104 wRC+, compared to 113 and 111 among neutral- and negative-environment hitters, respectively.
I don't have a fancy way to explain this, but a 7-9% difference in total offensive value is a pretty significant difference.
No doubt the Astros have done much more in-depth work in this regard, but after looking at the numbers, I wouldn't be surprised if the "developmental reasons" Crane cited while talking about the move from Lancaster were related to these very issues. If the move across the country will keep more hitters in the system, and more of them performing at a high rate once they graduate from High-A, that can only be a good thing