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Friday, June 23, 2006
How has the “new” use of the humidor affected the 2006 Rockies?
Using batted ball data from STATS Inc., I took a look at flyball distances and HR rates per fly ball at Coors Field and in other parks in order to get an idea as to how the use of the humidor has affected the HR rate and run scoring in general at Coors Field, and whether the so-called “new” use of the humidor this year has “really” affected the baseball.
There is little doubt in my mind that the “new” humidor in 2006 is making the balls heavier and wetter than a typical major league ball, despite declarations to the contrary by MLB and by the Rockies themselves (that the humidor merely restores the original specifications of the baseball). Altitude certainly has a profound effect on fly ball distance and hence HR rate (depending on the size of the park of course). I doubt the dry air in Colorado by itself has much of an effect on the ball, and hence fly ball distance, HR rate, and run scoring. Are there not other venues that are quite dry as well (Arizona for instance)?
Here are the average fly ball distances and HR rates per fly ball at Coors Field since 2000, along with the average fly ball distance and HR per fly ball at all other parks:
(All 2006 data is as of June 1)
Coors
00 336 .174
01 340 .192
02 334 .155
03 334 .149
04 336 .167
05 333 .139
06 329 .113
All other parks
00 322 .134
01 322 .131
02 321 .122
03 321 .125
04 323 .133
05 324 .125
06 325 .131
Keep in mind that the fly ball distances for the first 2 months of the season are around the same as for the whole season.
It should be obvious from the above data that originally the humidor cut the average fly ball distance by around 5 feet starting in 2002. In 06, it has been cut down an additional 5 feet. This could be a random fluctuation (not likely) or it could be a function of the hitters and pitchers on the Rockies. Let’s look at their road game fly ball distances (both teams) and HR per fly ball to see if in fact their hitters and pitchers are producing shorter fly balls than in the past:
00 317 .105
01 320 .139
02 322 .117
03 320 .121
04 325 .143
05 325 .117
06 324 .096
So the fly ball distances on the road have not changed much this year, suggesting that it is not the Rockies’ batters/pitchers that are causing the shortened distance in Coors this year, but rather the “new” use of the humidor (as opposed to 02-05).
As you can also see, because Coors Field is a very large park, especially the left side, even when the fly balls are 4 or 5 feet further than in other parks, as they are this year, the HR rate is significantly less than in other parks. So basically Coors Field has become a very low HR park, but obviously singles, doubles, and triples (especially the latter two) will still be increased because of the spaciousness of the park and because the ball is still being hit a little bit further and harder than at other parks because of the altitude.
Arizona is a hot and very dry venue with an altitude of around 2000 feet (I think). The average fly ball distance there is only slightly higher than in their road games. ATL is hot and humid and at around 1000 feet in altitude. The fly ball distance at home is much greater than in their road games. I don’t think that being dry has much to do with how far the ball travels or HR or run scoring in general. I think that the altitude in Colorado was the primary if not the sole reason for the high HR rate and run scoring prior to the humidor and I think that the effect of the humidor is to make the balls heavier and/or wetter than the typical major league baseball.
By the way, to see whether Coors Field affects the home team and road teams differently, as well as the Rockies Road Hangover affect, here are the fly ball distances and HR per fly ball for the home and road teams in Coors Field and in the Rockies road games:
Coors Field
Year Rockies Visitors
00 336 .163 336 .184
01 338 .181 341 .202
02 331 .135 336 .174
03 337 .149 331 .149
04 337 .174 336 .160
05 334 .140 332 .138
06 327 .080 332 .143
Rockies Road Games
Year Rockies Home Team
00 312 .076 322 .137
01 319 .136 321 .141
02 317 .099 325 .132
03 321 .122 320 .120
04 328 .147 322 .138
05 324 .109 326 .125
06 327 .117 320 .071
Typically the home team and the road team have around the same fly ball distance and the HR per fly ball is slightly higher at home (probably the home team fly ball distance is a little greater).
If we look at the Rockies and their opponents’ data at home and on the road, it appears as if the Rockies really suffer on the road as far as their fly ball distance and hence their HR rates are concerned. Their average fly ball distance on the road from 00-05 is 321. For their opponents in their home parks it is 322.7.
This does not seem to be true this year thus far. It may in fact be that the “new” humidor use has cut down or even eliminated the Coors Field Hangover effect. It will take more and different data to determine that. Since I had the fly ball data handy, I thought I would look at the home/road breakdowns. To analyze the hangover effect, all of the component data need to be looked at.
One thing that bothers me about “average HR distance” is this: say that a park reduces flyball distances by 10 feet. And figure that 80% of HR would not be affected by the shortening, but the other 20% would become warning track plays.
Say that the average HR distance of the 80% if 340 feet, while the average HR distance of the other 20% is 320 feet. (Total average is 336 feet.) Now, if the FB distance is reduced by 5 feet, say that the 80% HR now is 335 feet, but that the 20% HR now all become long fly balls. The average HR distance is 335 feet.
So, you really gotta be careful here. What you should do is take the 10% longest flyballs hit in a park in 2005, and compare that to 10% longest flyballs hit in 2006. (Or you can use 13% instead.)
Or, also break it down by the direction (left, left-center, center, right-center, right), and take the 10% longest in each direction. Using HR distances will lead to problems.