Babip Baby!

Hardball Times did a great article kind of dissecting BABIP (batting average on balls in play), sorting out players that really outperformed or underperformed their expectations. According to their glossary they explain it as "Batting Average on Balls in Play. This is a measure of the number of batted balls that safely fall in for a hit (not including home runs). The exact formula we use is (H-HR)/(AB-K-HR+SF) This is similar to DER, but from the batters perspective." And the Wikipedia entry does a good job explaining it as well. Essentially someone can't sustain a high or low BABIP. A pitcher who's ERA is really good but had an inordinate amount of balls in play turn into outs likely was lucky and won't repeat that next year. On the hitter's side, if a hitter has an inordinate amount of balls in play turn into hits leading to an inflated batting average, he shouldn't be expected to hit that high again.

So, in the article they used more data to find a hitter's expected BABIP and compared it to their actual BABIP to see who was unlucky and lucky in 2008. According to their findings players like Nick Swisher and Jason Giambi should rebound this year. That is pretty fascinating considering Giambi actually had a productive year, 12th in the AL in OPS. You can expect Billy Beane to be all over that and sign Giambi. Also, it's safe to assume Brian Cashman was on his game acquiring Swisher for very little expecting a return in 2009. Some other pointers, maybe Milton Bradley will be overpayed due to luck and some youngsters like Soto, Kemp, and Aviles may regress.