Batting average on balls in play is often pointed to quickly as the reason a player will rebound or take a step back in the future. Regression is a two-way street, and BABIP is often at the center of it. Not all cases are like that, though: the .290-ish BABIP that tends to be the league average is just that -- an average. Not every hitter is going to stick in that zone, as you've got high- and low-BABIP players among the league's hundreds.
Adrian Gonzalez has consistently been a high-BABIP hitter in his career. That fact has been hidden by his former home park, Petco, as that place -- lovely as it is -- is the bane of many a hitter's existence. Gonzalez hit .307/.381/.579 on the road as a Padre, and just .267/.367/.442 at Petco. Thing is, that "just" was still a Herculean effort in that environment.
Notice the lower batting average? Much of that has to do with the hit-suppressing Petco. Have a look at the BABIP of Gonzalez, the league, and Petco from 2006 through 2010:
Petco was, on average, 21 points worse than the league average in BABIP in this five-year stretch. Gonzalez, on average, was 34 points ahead of Petco, and 13 points ahead of the league despite playing half of his games in San Diego. He posted better-than-average BABIP rates while at Petco, but on the road, things opened up for him that much more.
Getting into Fenway Park last year helped even more. Gonzalez posted a .380 BABIP -- highest of his career -- but did so while in a park that consistently is above the league average in terms of batting average on balls in play. In 2011, Fenway's BABIP was .322 -- it's no wonder Gonzalez posted a home BABIP of .402 last year, with that kind of environmental assistance. From 2006 through 2010, Fenway BABIP was an average of 33 points higher than Petco's, and 12 points ahead of the league.
Expecting another .380 season from Gonzalez, or one every year, is maybe asking a bit much. But it's clear from the history of Gonzalez, Petco, and Fenway that he's capable of consistently high BABIP in the .340 to .360 range -- that's not that far from .380, and with the natural ups and downs of numbers like this on a year-to-year basis, we shouldn't be surprised about Gonzalez's 2011. Or a repeat in the future.