Friday, May 29, 2009
An aside on Jeter’s defensePosted by Colin Wyers
Sometimes, you take things for granted. I took for granted that people understood that Derek Jeter isn't a very good defensive shortstop.
And most regular readers of THT, and particularly what I write, are aware of this. Pretty much every advanced fielding metric ever devised thinks that Derek Jeter is a subpar defensive shortstop. This has gotten to the point where even Slate is writing about it. So when I put in a chart in my SZR article that showed Jeter with the second-lowest Plus/Minus totals for a career, I made an offhand remark based upon this fact and thought it needed no further examination. Quite frankly, I thought it was the least interesting finding in the article.
Some people disagreed.
Before I begin, I should clarify something: Derek Jeter is not the worst defensive infielder of all time. He is merely (according to the data presented) the worse defender to play shortstop relative to his peers for 17,563.0 innings (and counting). That's a vastly different thing; shortstops are typically the best defensive players on their teams (absent the battery, which is an entirely different matter). Jeter has played a demanding defensive position for 15 seasons, and while he has played it worse than average, you can't simply take that away from him. About all you can really say is that Derek Jeter has a very good chance of being the worst defensive shortstop in the Hall of Fame. There's no real shame in that.
As far as the worst defensive infielder of all time? We'll never really know for sure, I don't think - if they can hit, they become David Ortiz; if they can't, they end up being a minor-league journeyman. Either way, they don't stick around long enough for us to figure out how bad they are.
But the larger point I want to make is this. We all know that defensive metrics aren't perfect, for a number of reasons. And we always need to be careful of checking our work when what our numbers say conflict with conventional wisdom. SZR as originally published listed Hal Chase as a historically bad fielder; after examining more closely, it seems that Chase "breaks" the way that SZR assigns plays to first basemen, by taking the majority of his plays himself. He has astronomical putout totals and almost nonexistant assists, and that gums up the works. Once the error has been identified, we can - and should - fix it. I'm already working on a revised version of SZR, and I guarantee you this one will be a lot smarter about Hal Chase. But the data isn't wrong simply because you want it to be. And in Derek Jeter's case, there is a preponderance of evidence - that well predates SZR - that points toward the idea that he was never a great defensive shortstop.
And, one more thing. I can assure you that I didn't set out specifically to make a metric about Derek Jeter and force everything to fit. I've laid out my methods, and am willing to answer further questions about them as necessary. All of the data I used is available for free download. If you want to disagree with my conclusions, please feel free. If you want to critique my methods, please do so - I have learned a lot from civil discussions like that, and that's going to make SZR a better system. You don't need to call names or question my integrity to make your point.
Colin Wyers knows exactly how much of a nerd he is. He is very interested in hearing about any other concerns you may have; you can reach him by e-mail, and he will try his best to respond in a timely fashion. He also blogs at Statistically Speaking.