The Last, Greatest Post About Austin Jackson & BABIP: Part 3: BABIP Projectability

This is a sample restricted to only those players who have had at least 300 plate appearances at AAA between 2006 and 2010 and have seen at least some action in the big leagues as well.

AJax is well-positioned on the list, but an exceptionally high BABIP at AAA doesn’t seem unique, at least for a prospect with a legitimate shot at the big leagues. Some of these are guys who were highly touted prospects and/or already established major leaguers – but they aren’t necessarily the guys you expect to be winning batting titles and (with the exception of Matt Kemp) I don’t know that any of them would really seem to be ‘defined’ by their BABIP abilities. A high minor league BABIP doesn’t seem, by any stretch of the imagination, to be a guarantee of a high major league BABIP. Like any other skill, your best guess should be to ‘deflate’ AAA numbers in order to project what the player is likely to achieve in the big leagues and then, only then, if the player really ‘pans out’ in a certain sense you might see him beat your projections and maintain his minor league output.

This is how it works for other offensive metrics, this is how it works for BABIP as well. If we take all the players with at least 50 PAs in the majors and 50 PAs in AAA between 2006 and 2010 and look at the (unweighted) average stats, the average hitter put up a .322 BABIP before getting the call-up and only a .290 BABIP afterwards. Our BABIP deflator, in a crude sense, could be 32 points. For batting average, the (unweighted) average player hit .278 in AAA then only .242 in the bigs – a deflator of 36 points. For isolated power, the AAA average is .156 the MLB average .127 – a deflator of 29 points. An average player will see his strikeout rate rise by 5.6 percentage points and his walk rate decline by 1.2 percentage points when he makes the transition. Now, something worth noting here: the reason that we ‘deflate’ all these stats if we’re projecting how a hitter will do in the big leagues is that the quality of the pitching is better in the majors than it is in the minors (logically). If there is anyone out there who still argues that pitchers have no influence over BABIP – this data speaks otherwise. If major league pitchers were no better at controlling the outcomes from balls in play than AAA pitchers, we would see deflated power, deflated BA solely due to rising strikeout rates, etc… but AAA BABIP and MLB BABIP would be exactly the same.

If we look at Jackson’s AAA numbers alone and apply these deflators, we would expect him to have a major league BABIP of .369, batting average of .263, ISO of .078 K rate of 27.8% and a walk rate of 6.3%. His true numbers, in a sample size that is admittedly not as large as one would like, is a .381 BABIP, .281 BA, .112 ISO, 27.9% K rate and 7.3% walk rate. Jackson has beaten the projections, so far, which says little more than that he hasn’t been a bust. In particular, he has seen no drop in power or walks as he has made the transition – but he hasn’t seen a real rise either. His strikeout rate has risen every bit as much as a projection based on AAA numbers would predict – which isn’t good – and his sustained value in the lineup is due primarily to a BABIP that has not just beat the projection but beaten the projection despite an expectation of additional ‘regression to the mean’. Why regression to the mean? Well, no one sustains a .390 BABIP in the major leagues – period. The guys that had the highest BABIPs in AAA also tended to have the largest drops when they moved up. BABIP is a real skill, it isn’t just luck, but there is still a lot of luck and a lot of variance from season to season.

We can believe that BABIP is a real skill for Jackson, while it probably isn’t for someone like Chris Ianetta, because he maintained a high BABIP in the majors and perhaps more importantly had a high BABIP throughout his minor league career, which spanned 5 seasons and almost 2500 plate appearances. BUT, his minor league BABIP wasn’t .390, it was a more plausible .365 – equalling but not surpassing Rogers Hornsby. If we deflate that .365, we would get a BABIP projection of .333 – which is quite good assuming a player with some other skills, but probably not good enough to compensate for Jackson’s lack of power or strike zone discipline. Given how he has performed thus far at the major league level, I am not at all uncomfortable projecting a ‘true’ BABIP for Jackson based on talent alone in the .340s rather than the .330s – which still will require improvement in other areas for Jackson to be an outfielder at league average or better.

For some food for thought, here’s the minor and major league BABIP numbers for the rest of the current Tigers squad.

Check back tomorrow for the fourth and final installment: ‘Variance’