What can Crash Davis teach us about Denard Span?

"Know what the difference between hitting .250 and .300 is? It's 25 hits. 25 hits in 500 at bats is 50 points, okay? There's 6 months in a season, that's about 25 weeks. That means if you get just one extra flare a week - just one - a gorp... you get a groundball, you get a groundball with eyes... you get a dying quail, just one more dying quail a week... and you're in Yankee Stadium."
-- Crash Davis (Kevin Costner) in Bull Durham

I've always found it funny that buried in the middle of Bull Durham - a movie so enamored with the traditions, soul, and history of baseball - is a quote that feels right at home in the modern statistical analysis of the game.

I started thinking about this quote the other day when I was digging through Denard Span's 2010 statistics. To say it's been a disappointing season for Denard would by a huge understatement. The following chart should sum it up nicely:

For those on the b-squad mathlete team, that's a 124 point drop in OPS from last season. In 2009, he was ranked as the third best offensive center fielder in baseball (using wRAA). This year, he ranks somewhere between Cody Ross and Drew Stubbs in terms of offensive production.

But then I'm reminded of the quote from Bull Durham and it's implications for how we measure offensive performance. No matter how simple or advanced the statistical measure, a large portion of a hitter's overall value comes from his sheer volume of hits. Yet while a player's total hits (and batting average) are largely based on a batter's skill, they're also subject to the vagaries of funny bounces, misplays, and, well, random chance.

Here's why I bring this up: even for statistically-inclined fans, it's easy to fall into the trap of just looking at a player's OBP and SLG and made some pretty broad assumptions. The problem is that both OBP and SLG are largely comprised of a player's batting average (hence OPS actually double counts batting average). Span's batting average has dropped 46 points from 2009. That means of his 124 point drop in OPS this season, 92 points are due to his drastically lower batting average. Yes, his walk rates are down a touch, and his power numbers have dropped too (I'll expand on this below), but Denard's biggest problem in 2010 has been getting base hits.

So how much of Denard's drop in batting average is due to an erosion in skill and how much is due to bad luck? Well, it's a good question that's worth some debate and discussion. Here's what I do know: Denard's batted ball profile - his rate of groundballs, line drives, and fly balls - looks very similar to what he did last year:

However, there's been a huge difference in how frequently those batted balls have turned into hits:

Across the board, we see Denard experiencing a sharp decline on the number of batted balls that have avoided fielders' gloves. Now, I, for one, am not willing to simply chalk up these differences just to luck. A hard hit ground ball has a better chance of sneaking by a fielder than a slow chopper to first, and we've all seen Denard hit his fair share of choppers to first this season. But given the fact that Denard still has very good speed, and his batted ball profile remains relatively unchanged, it's hard to say that he hasn't experienced some bad luck on his BABIP (especially on ground balls).

Taking into account Denard's speed and batted ball profile, the freely-available BABIP estimator at hardballtimes.com suggests we should expect a BABIP of .340 for Span. That's certainly a lot closer to his 2009 performance than what we've seen in 2010. While we can debate the merits of "expected BABIP" and whether or not Denard has or has not been unlucky, it is interesting that if Span did have a BABIP of .340 this season, his current slash stats would be .301/.370/386. That's roughly what Brett Gardner and Ichiro have hit this season.

Of course, we can't ignore the very real decline in Span's walk (BB%) and power (ISO) rates, which are much more difficult to chalk up to luck or randomness. Take a look:

That's two straight seasons of declining walk and power rates, and a very real concern. But let's be careful about making any broad proclamations about Denard becoming a free-swinging slap-hitter. Even his suppressed walk rate is above league average, and only six batters in baseball have swung at a fewer percentage of pitches outside of the strike zone. In fact, the scouts at Inside Edge have actually judged Span's plate discipline in 2010 better than it was in 2009.

And, yes, his Isolated Slugging has taken a downward slide, but would you believe he actually has more extra-base hits per at-bat this year than last? The difference in his ISO isn't based on a lack of extra base hits, it's based on the fact that Denard is hitting more doubles this season, but fewer triples and homers. Now look at where his homeruns were landing last season - isn't it entirely possible that the difference in his ISO has to do with two or three fly balls that snuck over the fence last year that have fallen for doubles this season?

Now I don't mean to sound like a Denard apologist. His offensive production has been a huge, huge disappointment this year, and he's made no friends with his baserunning and defense. Plus, like many fans, I can point to my own subjective memory of watching the Twins play this season and say that something just looks different about Span this year when he's at the plate. And yet, when we look at the facts I laid out above, a good case can be made that Denard's disappointing season is the product of a slight downturn in production magnified by some bad luck and (perhaps) playing a little over his head in 2009.

No matter how much blame you put on Denard and how much you're willing to chalk up to random chance, it's important to remember that Denard's biggest problem right now isn't drawing walks or getting extra base hits, it's having batted balls turn into hits. In essence, it's what Crash Davis said was the difference between riding a bus at AAA and playing at Yankee Stadium.

So, Twins fans, we're left to ponder whether Denard's low BABIP the result of something he's doing as a hitter, something opposing pitchers are doing to him, or a random fluctuation that will eventually even itself out. If you have a theory, post it below. I'd love to hear it.

Note: I wrote most of this article Tuesday morning, and am just putting the finishing touches on it Tuesday evening. I now see Brady Eyestone wrote a FanPost on Denard Span, as well. Great minds think alike, I guess. I recommend you check out his piece as well for another perspective on Span's season.