Beware the BABIP

I harp a lot about BABIP (Batting Average on Balls in Play) and how it's a good indicator if a player is due for a slump or a rebound from year to year, and even within a season. The general guideline is that a player will generally settle within a range of .290-.320 on their BABIP, with the league average being .300 for a hitter and .290 for a pitcher. Now pitchers have much less control over their BABIP than hitters, that is unless they throw a knuckleball or particulary good change-up that is hard to get good contact on, but hitters actually can outperform or underperform that guideline quite significantly thanks to an ability to hit line drives, speed and a few other minor factors. That being said, they don't outperform it by that much. If you look at the 3-year leaderboard for BABIP on Fangraphs, only three players have topped the .360 mark (Jeter, Holliday and Chipper Jones with Ichiro just missing). Now those are some of the best hitters in the game and their career BABIP's are pretty high as well (except for Chipper who has a .328 career BABIP) and it's been shown that players regress more towards their own BABIP levels than the league averages. That all being said, when you see a player hitting anything over .340, you need to start worrying that it will fall back a bit unless they've been able to sustain it for a few seasons. On the flip side, if a guy is suddenly below .280 he's either had a really unlucky season or he's about to leave major league baseball (see Jones, Andruw).

People smarter than me and with way more time have been trying to calculate exactly what influences BABIP and a recent study posted at The Hardball Times has made some headway on the topic. Now with the advent of keeping track of batted ball types (line drives, ground balls, flyballs, infield flys, etc)  a bit of an illuminance has been shed on the subject.  At one time, it was suggested that if you add .120 to a hitter's line drive percentage, you'd get a fairly decent approximation of what their BABIP should be...the harder you hit a ball, the harder it is to catch it.

That recent study broke down BABIP even further and came up with a better mousetrap to guess what a player should be doing using speed, line drive percentage, ability to hit to all fields and much, much more. The results are interesting and their model seems to be the best estimator out there at the moment. 

I've listed the Cubs results below but let me explain an interesting discrepancy. Fangraphs has their BABIP for each individual season and their career and that's what you'll see in the first three columns, their 2008 BABIP from Fangraphs, their career BABIP from Fangraphs and the difference. The BABIP for 2008 in the spreadsheet provided by the authors of the THT article differs slightly and is said to be taken from Baseball Prospectus. Why the difference? I'm not sure, but I assume they calculate it slightly differently and why that is I don't know, but know that the BP BABIP numbers are lower than what Fangraphs calculates, although generally just a few points. To compare apples to apples, the second three columns compare the BP calculated 2008 BABIP versus their xBABIP as the THT article calls their new BABIP estimator. And for some reason, they don't have an entry for Mike Fontenot for 2008.

So whatever column you're looking at, you can see the Cubs hitters certainly enjoyed some good luck last season. Almost across the board they outperformed their BABIP for their careers and what they should have gotten in 2008. Sobering news indeed...

Now, I would also kind of expect that from the number one offense in baseball, you'll get a fair amount of luck coupled with career years and the Cubs still out-OPS'd the Cardinals by .014 pts (who had a few of their own career years) and the Phillies by .027 points (the Phils offense is just good), so they have a bit of a safety net for the eventual fall the offense will likely take in 2009. 

Individually, I'm particularly worried about Theriot and Miles, and expect a pretty decent drop in their numbers. And while I do get on Theriot's case a lot, I will say that my observation has been is that he does have a knack for getting the sweet spot of the bat on the ball. The more you do that, the more solid contact and line drives he'll hit and the more the ball will fall safely for a hit. But I still expect his numbers to drop in 2009, although maybe not quite as steep as 30-40 points off his batting average. I already expected Bradley to fall of from his .999 OPS, and hell, he could drop 100 points off that OPS and still be the Cubs best hitter in 2009. The xBABIP estimator doesn't look good for Soto, but he's young and we don't know his career baseline yet and he could suffer a drop in his BABIP and make it up for it with more power as he's still just 26 years old this year.  If Reed Johnson gets to hit mostly versus lefties, I'm not worried about him dropping too much either.

I know I mentioned two articles for today, but one of the twins has been pretty sick, so you get one. We had three articles yesterday plus a game thread, so plenty to scroll back on and enjoy during today's off day.