There are only two home/away splits I pay attention to: Coors Field and Petco Park. For all other reputed bandboxes and pitcher’s parks, the splits are swamped by noise. Just check ESPN’s MLB Park Factors from year to year. Sure enough, for 2009, there’s Coors Field at the top and Petco Park at the bottom. But reputed bandbox Great American Ball Park is only 4/1000 above average this season in run production, despite being as high as 153/1000 above average in the past:

2009: 1.004
2008: 1.069
2007: 1.095
2006: 1.153
2005: 1.125

Pick a run-of-the-mill park like Progressive Field in Cleveland and you will see even more variation:

2009: 0.843
2008: 0.995
2007: 1.120
2006: 0.946
2005: 0.874

Now consider that when you play a home split, you’re playing just one game out of a whole season. Not only will the quality of the opposing pitching staff overwhelm the park factor, but so will sheer randomness.

Yet I am willing to recognize that Coors Field (like Petco Park) is an extreme case. Only once since 2001 has Coors Field been lower than third in run production — when spiking run production for several other parks dropped it to 5th in 2003.

The question is, for whom do you play the split? I have Seth Smith as my fourth outfielder but have avoided playing him much because he sits two games out of six. Apparently the Rockies think more highly of Carlos Gonzalez, despite Smith’s equivalent or superior minor league numbers (compare).

Now, the Denver Post reports that Gonzalez will take his starts from the slumping Dexter Fowler:

Carlos Gonzalez and Dexter Fowler are the Rockies’ two best athletes. Using a platoon, manager Jim Tracy is hoping to create a single terrific center fielder…. Gonzalez, who lost the left field job three weeks ago to Seth Smith, is now starting in center field against right-handers.

If this holds up — and you are in a league with very deep rosters — you can play the double-split: Gonzalez, at home, against right handers. Ignore for now the fact that Gonzalez has a better road than home split — give him time.