In 2010, the Rockies hitting was marked by two major problems: the dramatic split between home and road performances (The Rockies home wRC+ of 122 was second in MLB, and their road wRC+ of 68 was dead last), and the lack of good or even adequate performances by Todd Helton, Ian Stewart, Dexter Fowler, Seth Smith, Eric Young Jr., and most notably Chris Iannetta. Up to this point, many fans have chalked up last year's disappointment to a combination of age and busts. However, I think something more Luck-Dragon oriented was the root cause of 2010: BABIP.
BABIP stands for Batting Average on Balls in Play. It is simply a measurement of the amount of a hitter's balls in play that land for hits. It is very useful for determining how "lucky" a hitter (or pitcher) was over a sample of plate appearances. If you want to know more about BABIP, I would read this Fangraphs Sabermetrics Library article by Steve Slowinski.
xBABIP stands for eXpected Batting Average on Balls in Play. It is a metric that attempts to determine what a particular hitter's BABIP should be over a sample of plate appearances. It takes into account the batted-ball type percentages ("batted-ball profile") of a hitter, factors in their speed (essentially ability to leg out infield singles), and produces an estimation of what one would expect for a hitter's BABIP. This allows us to somewhat factor out luck for hitters, and adjust their batting lines to reflect what we would normally expect to happen.
With inspiration from this Hardball Times piece by Jeffery Gross, and with the use of Chris Dutton's "Simple xBABIP Calculator", I created a spreadsheet to adjust the batting lines of the returning cast members from 2010:
I found the results quite surprising. Every single one of 2010's "disappointments" experienced some amount of "bad luck." Our two biggest busts, Chris Iannetta and Seth Smith, had their lines incredibly depressed because of BABIP-misfortunes. They experienced a 20% and 11% reduction in OPS, respectively.
As I mentioned in my previous post, the 2011 Rockies look to improve internally rather than with outside talent. Looking at the xBABIP data, the team may not even need to improve, they just need to experience some well-deserved BABIP normalization.