The basic skinny is that there's a lot of randomness involved in what happens when a ball is put in play. Fielding, park effects, weather, dumb luck... all these play a part in how often hit balls are converted into outs. Research shows that pitchers really have no repeatable ability to affect BABIP.
Hitters are different. While there's a lot outside their control that affects BABIP, they can affect it with "true" skill. This analysis by Chris Dutton and Peter Bendix at The Hardball Times finds that hitter’s eye, line drive percentage, speed score and pitches per plate appearance all correspond with a higher BABIP, while there's a negative correlation between BABIP and pitches per extra-base hit, fly ball/ground ball ratio, spray and contact rate. All this I think fits what you'd imagine, but Dutton and Bendix did the fancy math to confirm.
Once Dutton and Bendix were able to quantify the extent to which each of these stats influence BABIP, they were able to create a "luck-neutral expected BABIP" for every player in baseball with a certain number of plate appearances. Here are the Nationals players from most to least lucky in their 2008 BABIPs:
|NAME||BABIP (actual)||x-BABIP||x-BABIP dif|
Because most people aren't used to looking at stats like BABIP, I took the Dutton and Bendix xBABIPs and crunched the numbers on what the Nationals' OBPs and BAs would have been in 2008. Again, from most to least lucky, here's what our guys would have done if luck hadn't been a factor in BABIP:
|NAME||Actual OBP||xOBP||Actual BA||xBA|
Just a few observations here:
- As I've noted before, Kearns had a lot go against him in 2008, and he almost surely wasn't as bad as he looks at first glance. A .340 OBP would have been more respectable, but really the biggest problem for Kearns was his total lack of power. And a .340 OBP isn't all that good, especially for a corner OF who's strength is supposed to be his on-base skills. I don't think there's a ton of evidence for a big bouce-back for him, though probably there will be some.
- As good as Willie Harris was in 2008, it's pretty stunning to consider that he really "deserved" a .371 OBP. I can't quite shake the feeling that maybe I'm missing the boat not calling for starting Willie in left in 2009, and this is another bit of evidence that he might be better than Willingham.
- There's nothing here to offer encouragement on the Jesus Flores front. Next year will be a very big year for him. I'm still hopeful, but I wouldn't be at all surprised if we're looking ahead to Derek Norris or Adrian Nieto by this time next year.
- Cristian Guzman was very, very lucky, and I really think we ought to have traded him to one of the contenders in need of a shortstop.