Saturday, February 15, 2014

Down on the Farm: Minor League Park and League Factors

We often refer to park and league factors when analyzing minor league performances.  Sometimes that occurs in a relative vacuum of facts to back up the assertions that get thrown around. recently had a nice series of what appear to be official stats for each minor league and minor league ballpark, the first time I have seen it put together in one place with an accompanying discussion.  If you are so inclined, I recommend going over to the Official Minor League Baseball website linked to the left and look them up for yourself.  I thought I would post some of the key ones for the leagues and home stadiums the Giants minor league teams play in.

American League:  4.5 R/G, .740 OPS, 2.7 HR%.

National League:  4.3 R/G, .723 OPS, 2.4 HR%

Pacific Coast League(AAA):  5.1 R/G, .778 OPS, 2.5 HR%

Eastern League(AA):  4.5 R/G, .725 OPS, 2.0 HR%

California League(High A):  5.3 R/G, .764 OPS, 2.3 HR%

South Atlantic League(Low A):  4.5 R/G, .704 OPS, 1.6 HR%

Northwest League(Short Season):  4.7 R/G, .699 OPS, 1.4 HR%

Arizona League(Rookie):  5.5 R/G, .721 OPS, 1.1 HR%

Dominican Summer League(Rookie):  4.6 R/G, .658 OPS, 0.7 HR%

One extremely important thing to notice is that power increases as a player matures.  Although Runs per Game remain relatively constant as you go down into the lower minors, power numbers become very low and HR's scarce because, well, young players bodies just haven't developed the bulk and strength to generate power.  That is a major confounding factor here that has nothing to do with the effects of the ballpark or the league.   What it means is that a .725 OPS in the AA Eastern League is not necessarily better than a .704 OPS in the Low A South Atlantic League in terms of league factors that are unique to the league itself.  In other words, if you took all the very same players in the SAL and transported them to the PCL ballparks using PCL umpires, they would probably not increase their OPS from .704 to .778.  But, if you give those same Low A players 3 years to mature and develop their skills, then put them in the PCL, they now probably would generate the higher OPS.

Now, let's take a look at Park Factors.  These are relative weights with 1.000 being average comparing offensive output in parks within a given league.  These relative weights cannot be used to compare parks in two different leagues.  In other words, a pitcher's park in the Cal League may be easier to hit in than a hitter's park in the Eastern League.

Chukchansi Park(Fresno):  .965 R, 1.093 HR, .955 H

The Diamond(Richmond):  .979 R, .866 HR, .979 H

Municipal Stadium(San Jose):  .847 R, .870 HR, .919 H

Lake Olmstead Stadium(Augusta):  .861 R, .542 HR, .939 H.

Volcanoes Stadium(Salem-Keizer):  1.168 R, 1.303 HR, 1.069.

As you can see, the Fresno Grizzlies play in a neutral park in a strong hitter's league.  Richmond plays in a park that suppresses power relative to a league that is relatively pitcher friendly already which may explain why Giants hitting prospects struggle in the EL more than those from other organizations.  San Jose is surprisingly quite pitcher friendly relative to the league, but the league itself is very hitter friendly, so the overall environment for San Jose hitters may still be slightly friendly.  As you can see, Lake Olmstead stadium in Augusta absolutely crushes power relative to the rest of the league which is already low due to the relative youthfulness of the Low A players.

I hope these numbers and discussion add some light to the heat of future discussions about league and park effects as they pertain to Giants prospect evaluation.


  1. Do Park and League Factors impact a prospect's development (and how)?

    1. Oh, I absolutely think they do. Hitters in the PCL, particularly the western half of the league have it way too easy and then crater when they are faced with a much tougher environment in a pitchers park(AT&T) in a pitcher's league(National). I think there are finesse/groundball pitchers who fall by the wayside in Fresno because the PCL is so unfriendly to pitchers who rely on movement as opposed to velocity. The Giants AA team plays in a pitcher friendly park in a pitcher friendly league. I believe there has been more than one Giants hitting prospect psychologically damaged by the hit that takes on their numbers. I know a lot of that is just a feeling or belief I have, but if you look at the numbers, those beliefs are not without foundation.

    2. Maybe a better term would be psychologically set back rather than damaged. On several occasions, Sabes has mentioned the differences in environment between Richmond and Fresno and the impact that has on decision making in regards to prospect development and promotion.

    3. I would go with damaged when the Giants were playing at Dodd Stadium as the Norwich Navigators. There would be guys who hit really well on the road, but Dodd would just suck all of their power out. For example, Ishikawa was a thinker who let things bother him, and while he hit OK on the road his first season there, he was horrible at home and ended up repeating AA, at which point he just totally cratered. He later provided us some value but that cost him one year of development, at least, since I think it set him back too. Not that it hurt everyone, Sandoval killed there (though again, much worse in Dodd), so I guess what I might say is that it may have costed us the marginal players who would rise and be useful complementary players, as it just killed the tweeners and below.

      I documented that on my blog while we were still there. Richmond, according to the park factors I saw before the Giants affiliated with them, was more of a a neutral park when the Braves were there (also, I think it was a different level as well). Seems to be similar now that the Giants are playing there, though it is still a power sucker apparently, looking at the stats above, but I recall Dodd being worse, though .866 is pretty bad still. But that .979 run factor suggest that while the homers go down, the run environment is still relatively good, so probably a lot of those homers became doubles and triples so that the number of runs isn't affected by that steep drop in homers. And I would note that Adrianza could never figure out how to hit in that league, but once he got to AAA, he started banging the hits left and right, performing much better.

      Here's an example I would give on how park factors could affect a prospect. A while back, the last time the MiLB did such a study, Mayo found that San Jose's home park was one of the most extreme strikeout parks in the minors, boosting it a lot. Bowker was interviewed about this issue and agreed, noting that the background made it hard to see the balls at time. That could hurt both hitters and pitchers.

      Prospects at the lower levels, not all of them are stone-cold confident in their abilities, so experiencing this could affect them negatively. Hitters, they might start doubting their abilities to hit or maybe start swinging at more pitches out of the zone, getting into some sort of bad habit that takes away their ability to hit better. Pitchers, they could think that they can pitch to certain areas of the strike zones because of the poor background, and then get beat like a dirty rug once they get promoted, as they continue to pitch in the way that is successful in San Jose but not elsewhere. Subtle changes can creep up on players, especially if they are not sure what they need to do to be successful and still learning (for example, Bumgarner has said in interviews that he didn't know how he was successful as a pitcher before, he just threw, and sometimes he had it and sometimes he didn't. He learned how to be consistently good while with the Giants. And he's one of our top and talented prospects, just imagine how our lesser prospects not knowing how they are when they are successfully performing).