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More about Austin Jackson, small sample sizes, and BABIP

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So much has been said about Austin Jackson's hot start, and with Curtis Granderson struggling and currently sitting on the DL, some of the conversation here at Pinstripe Alley has questioned the wisdom of the three-team trade that sent AJax to Detroit.  I want to take some time to explain the argument against AJax's performance this season and hopefully, save Brian Cashman's metaphoric head.

I think most of us understand the statistic Batting Average on Balls in Play.  If you don't, take a look here.  Surprisingly, unlike WARP3 or UZR, you don't need to be a stathead or mathematician to calculate it.  If you want to figure out anybody's BABIP, use this simple formula:


(Thanks, Wikipedia)

As you know, BABIP is used to measure the amount of "luck" that a hitter receives.  Now, I'm not suggesting that certain players aren't working hard or haven't truly earned the results of their effort.  What I'm simply saying is when a hitter swings a bat, he only has so much control over where the ball lands.  Certainly, he can try to pull it, or try to hit it to the opposite field, try to hit it on the ground or in the air, but only to a point.  Think about A-Rod's home run in Game 3 of the World Series last year.  It famously bounced off of a TV camera and was ruled a home run, but if the ball had landed just a few feet lower it would have been a double, and if it had been a few feet to the right, it would have been a foul ball.  Did A-Rod really have that much control over the precise location where the ball would land?  Of course not.  And that's exactly what I mean when I say "luck". 

An average BABIP across baseball is usually around .300.  In the minors, AJax's mark was about .360.   Currently, though, it's at .532.  That means, despite the best efforts of the opposing team's defense, when he hits a playable ball he winds up with a base hit more than 50% of the time.  This is high, but how high is it really?

Look at the list of the highest single season batting averages.  95 of the top 100 occurred before World War II. Obviously, the game has changed significantly, and as the game has expanded and integretated, the skill gap between the very best and very worst players has shrunk.  That generally explains why nobody hits .400 anymore.  But for kicks, let's look at some of those .400 seasons in terms of BABIP. 

In 1924, Rogers Hornsby hit .424 for the entire season, and using the formula, we can see his BABIP that year was .421.  In 1894, Hugh Duffy posted the highest batting average ever recorded for a season, .440.  Estimating for sac flies (which were not an official stat back then), his BABIP that year was around .430.  More recently, Rod Carew batted .388 in 1977, posting a .408 BABIP along the way, and Ichiro batted .372 in 2004 to go along with a .399 BABIP.  Are you sensing a theme?  

Even in the heyday of high batting averages, it was pretty tough to post a BABIP much over .430.  Today?  Forget about it.  And since nobody in the last 80-odd years has come within 120 points of AJax's current mark over a full season, and Jackson himself has only come within about 170 points over his minor league career, I think that leaves us with two options:  Either AJax has made an unprecedented jump forward and has truly redefined the limits of what a hitter is capable of in the 21st century.......or he's simply enjoying the best, unsustainable month of his or anyone else's life.

It's hard to say exactly what this means going forward.  As the balls inevitably stop bouncing his way, we don't know if it will translate to more groundouts, more strikeouts, fewer extra base hits, or what exactly.  But we do know that Jackson strikes out a lot (27% of plate apperances this season) and doesn't walk at a particularly high clip (8% of PAs this season), and we do know that he's actually striking out more and walking less than he did in the minors, which is usually not a sign that a player has made a great leap forward.  And that makes me think that, given average "luck", right now Jackson would be hard-pressed to match, let alone exceed, his .288/.356/.410 minor league batting line..

Obviously, time will tell, and we haven't considered his defense or baserunning.  Until he develops some more power or patience at the plate, though, my money is on Jackson hitting like a guy most teams wouldn't regret trading.