---

Monday, May 2, 2011

In Defense of Derek Jeter’s Defense?

As a team, the Yankees have had a pretty good start to the year, albeit with a few clunkers along the way.  However, the same can’t be said for Derek Jeter, at least offensively.  Following the worst full year of his career, Jeter’s hit .242/.308/.263 over his first 107 PA of 2011.  Even that line seems like it understates how poorly he’s been hitting.  From 2002-2010, Jeter had 1727 hits. Of those hits, 17.9% were either infield hits or bunt hits.  In 2010 he had the same percentage of IFH/BH.

In 2011, 39.1% of his hits are either IFH or BH.  He’s hitting the ball with no authority, and those numbers really hammer that home.  His BABIP this year is low (.264 compared to .355 career), but given the fact that so many of his PA result in weakly hit balls to the infield that’s not suprising and it’s not necessarily indicative of bad luck.  It doesn’t mean he won’t perform better going forward, but it’s going to have to happen in at least large part to tangible improvement and not just better luck.

Jeter’s offensive performance is especially alarming because for most of his career he’s cost the team runs defensively.  He’s hit well enough to compensate for that most of the time, but at this point it’s not looking like he can continue to do that. 

I haven’t been looking at defensive metrics as much as I used to as I’ve learned more about their limitations, but that doesn’t mean they are useless.  It just means we need to look at them with the understanding that they’re limited.  This is particularly true when we’re trying to get something useful out of a 25 games sample of them.

Before I look at the stats I’ll just say that visually I have gotten the sense that Jeter has made more plays this year on balls to his left than I’ve expected while watching the games.  It almost feels like to me that he’s playing more towards the middle, or maybe a bit deeper in general because there have been quite a few plays where the camera switches from the batter hitting the ball up the middle to Jeter in the picture moving towards the ball and fielding it.

First, here’s what zone rating says about Jeter.

Player

Tm

Lg

Pos

G

INN

Ch

PM

ZR

AvgPM

Avg ZR

Diff

RS

Jeter, Derek

NYY

AL

SS

24

214.7

80

69

.863

67

.838

2

2

INN: Defensive innings at position
Ch: Playable chances
PM: Plays made
ZR: Zone Rating (PM/Ch)
AvgPM: Estimated Plays Made over the same # of chances by an average defender
Avg ZR: ZR by average defender at the same position and in the same league
Diff: Difference between PM and AvgPM
RS: Runs saved compared to average

Zone rating is basically just the number of plays a fielder makes divided by the number of fieldable chances he sees.  Chances are defined as plays that are converted into outs at least 50% of the time.  So according to these numbers, Jeter’s converted 69 of 80 fieldable chances into outs, which is a zone rating of .863, or 86.3%.  The AL average SS has converted around 83.8% of their fieldable chances into outs. So if you multiply Jeter’s chances by that you see the average SS would have theoretically made two fewer plays, which means Jeter’s been about two plays better than average.  The run value of that is about 0.8 runs per play.

While that is encouraging, it needs to be tempered by a few things.  There is research that shows that there may be some range bias in defensive metrics, so there may be plays that Jeter isn’t making that he’s not getting penalized for because the stringers aren’t marking them as fieldable, where as they may be marked as fieldable for a player who got closer to them.  There’s also the possibility that Jeter’s gotten a higher than normal distribution of easily fieldable chances which are easier to convert into outs and that if he’d seen a more difficult distribution he’d grade worse.  But most of all, the biggest issue is that 24 games thing. 24 games of defensive metrics are a very small sample on which to base much.

If there is range bias, I was thinking it may show up in terms of fieldable chances assigned to Jeter relative to other AL shortstops. 

Team	Pos	%
Oak	SS	22.1%
Bal	SS	20.9%
CWS	SS	20.3%
Sea	SS	19.1%
Tex	SS	18.6%
NYY	SS	18.5%
Min	SS	18.2%
Det	SS	18.2%
Cle	SS	18.1%
TB	SS	17.8%
Bos	SS	17.1%
KC	SS	16.9%
LAA	SS	16.8%
Tor	SS	16.0%

These are the percentage of fieldable chances assigned to SS by team so far this year.  This isn’t necessarily a great way to try and determine if there’s a range bias since it’s as much a function of the types of pitchers a team has and who they’ve played so far as anything else but I suppose it works as circumstantial evidence that if there’s a range bias that makes Jeter look better than he should the effect to this point isn’t big. [that’s one hell of a run-on sentence, isn’t it?]

That’s just one defensive metric.  Here’s what the FanGraphs defensive metrics say
John DeWan’s DRS: 0
UZR: 0.5

So ZR says he’s been +2, DRS says he’s been average, and UZR says he’s been a hair about average.  I think I am comfortable in saying Jeter’s defense hasn’t been an issue so far.  What I won’t say is that I’d expect it to last.  Jeter projected around -10 heading into the season so maybe now we should project him to end the year in the -8 area.  So he really needs to start hitting better if he’s going to end up above replacement level.