If you are a prospect nerd, it’s context that you want every year: how much did a particular ballpark impact the stats of the players we track throughout the year? Just like Major League ballparks, minor league parks sometimes skew pitcher or hitter-friendly thanks to the shapes, the altitude, the humidity, and the wind, among other things. Knowing just how much the parks skewed in a given season can help us better understand the prospect performance we’ve been evaluating. That’s what “Park Factors” are.
Most of you are now familiar with the wRC+ statistic, which gives you a better sense of how a player is performing relative to the league. But you need to know that, although Major League wRC+ adjusts for league *AND* ballpark, the minor league wRC+ adjusts *ONLY* for league. That definitely helps get you a good distance toward understanding the performance, but knowing the park factors really helps, too.
Baseball America just released the Minor League Park Factors for 2022 for the four full-season levels, which gives us an updated sense of the offensive environments in which the various levels of Cubs prospects were playing. It’s more context for their performance.
There are three Park Factors worth knowing: Runs, Home Runs, and BABIP. The first gives you the overall scoring sense, whereas the latter two give you a sense of how easy/hard it is to hit a homer or collect extra hits in a given ballpark. Give the full BA article a read here, but the high points on how the Cubs’ minor league ballparks played in 2022:
One thing that really, really leaps out at you: all three of Iowa’s home park, Tennessee’s home park, and South Bend’s home park played very home-run-friendly this year (ranging from 19% above average in South Bend to 17% above average in Iowa to 12% above average in Tennessee). That was generally true for the upper two levels last year, too, but not South Bend, which was slightly home-run-unfriendly last year. Not sure what changed there, because I’m not aware of any dimensions changes and that’s a dramatic swing. More wind assistance than average this year? A team that just happened to be dramatically more homer-binge’y at home than on the road? A partial fluke? No idea.
In any case, though, you do have to keep that context in mind when you talk about the big home run numbers for guys like Matt Mervis and Alexander Canario, among others. To be sure, you’re talking about a boost of maybe a couple homers on the season, relative to the expected home run totals if they played in different home parks, but it’s a factor.
Conversely, for the pitchers who called those three parks home in 2022, you can think about the guys who were disproportionately stung by long balls. How much of that was their own performance, and how much of it was some bad park luck?
At Myrtle Beach, you already know this: it’s just a brutal place for home runs. A Park Factor of 78 means it is 22% less homer-friendly than the average park in the league.
Keep in mind, that’s just home runs, and that’s only one part of the overall run-scoring environment. For example, it’s actually the case that Iowa is overall the most offense-friendly ballpark in the system, with a Runs Park Factor of 111 – 11% more offense-friendly than average for the league. The bats were likely getting a little boost at home. The pitchers were likely getting a little ding.
Overall, Tennessee’s ballpark was exactly average in run scoring. South Bend was 5% more offense-friendly. Myrtle Beach was 16% more offense UN-friendly – it’s one of the more offense-suppressing ballparks in MiLB. That makes a lot of the great pitching transitions from Myrtle Beach to South Bend this year all the more impressive. Also makes offensive performances like Kevin Alcántara and James Triantos down there look a whole lot better.
Check out the full slate of Park Factors here – some are kind of hilarious around the leagues – and think about the implications for Cubs prospects and other prospects in player evaluation. I will be mulling them more over the course of the offseason.
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