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What’s Ailing AJ?


Like most of you, I want more Blastro. Fans appreciate Pierzynski  for his “whatever it takes” attitude, but if AJ was truly about winning at all costs, he might consider volunteering to ride some pine. Pierzynski’s feckless flailing this year has equaled a .238/.273/.349 line, his worst offensive season to date.   Converted to runs, Pierzynski’s bat has been worth -4 runs below a replacement level player. His only saving grace is that the offensive bar for catchers is so low.  But with Ramon Castro hitting with almost every opportunity he gets, it’s hard to justify AJ continuing to get so much playing time.

So what’s the deal with the AJ? Let’s slice up his production by parts of the plate and see what’s up. First here’s his wOBA on pitches he makes contact with by pitch height.

I’m not totally sure how instructive these graphs are, but it looks like AJ isn’t his normal low-ball swinging self, or high-ball hitting self, either.

Here’s his wOBA on pitches he makes contact with by vertical location.

The postive numbers is AJ’s side of the plate as a lefty hitter, and it seems  he’s struggled with pitches inside, and he isn’t getting much done with pitches on the outer half, either.

Keep in mind this is BABIP influenced, and since we’re on the subject of AJ’s woes, I think we have to talk a little BABIP.

BaconSlayer09 (great moniker) recently took a fantastic look at Mark Kotsay’s bad luck through the lens of xBABIP and found that despite hitting into a few too many “hang wiffems”, Kotsay still is terrible. I thought I’d give AJ the same treatment and see if he’s been just unlucky, or truly terrible.

Pierzynski’s BABIP is a miserable .243. His career BABIP is .301 and based on his batted balls, his xBABIP figures to be .297, much more in line with his career rate. Not including his homers, he’s put 324 balls in play. Multiplying that by 29.7% and we get 96 hits, 15 more hits than AJ has, and after adding back in his 6 homers, we get a .299 batting average. That’s a pretty huge difference. That would bump his on-base percentage to a much more respectable .329, and assuming his rate of doubles remains true, we get a .419 slugging. Hey, that’s the AJ we’re a little more accustomed to.

Converting this all to wins, AJ would be a 1.8 WAR player, up from 0.4. That’s more like it.

I wouldn’t stick a fork in Pierzynski yet, but it will be interesting to see what the Sox decide to with him in the offseason. He is amazingly still on track to be a Type A free agent, but I would think he’d probably jump at the opportunity to accept arbitration of offered. With the Sox’s payroll where it is now, I think a Tyler Flowers/Blastro combo would represent potentially equal output at a fraction of the cost, assuming Castro would be willing to re-sign somewhat cheaply. It would be a considerable upgrade if you think AJ’s weak-hitting ways are the real deal.

Yes, Flowers has taken a step back this year, but is that step really so big? His batting average is way down, but he has a 12.9 BB% rate to go along with a .232 ISO. He’s hitting more line drives – 20% vs. 13.5% in ’09, but his BABIP has dropped .087 from where it was last year. He’ll be fine.

2 Comments leave one →
  1. 2010/08/14 6:26 PM

    Interesting read. I agree offensively with you about AJ, but the White Sox and AJ would argue that his true value is his effect on the pitching staff. I’m curious if there are any ways to measure the effectiveness a catcher has on a pitcher’s numbers.

    • 2010/08/14 9:42 PM

      Thanks for your comments, Adam. I’m agnostic when it comes to game calling. Keith Woolner did a study and found that catcher “game-calling skill” isn’t a statistically significant skill, or at least not one we can detect. Catcher ERA is a junk stat because it doesn’t take into account ballparks, the other fielders and perhaps most importantly, who is pitching.

      I have read another study where the effect of having a rookie catcher was pretty staggering, like an ERA composite of .40 runs higher than when throwing to veteran catchers, but he only seemed to have looked from a small pool of players. I don’t know if I trust the results.

      I would think with this day of pitch f/x we’d have more answers by now, but I’m sure it’s hard to get the noise out of the data. One thing we do have with pitch f/x data is that catchers “frame” pitches better than others. It’s not one of AJ’s strong suits, he’s average in that regard.

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