Mood Music - Going Down to Die by Danzig
When I've got free time, I like to be as nerdy as possible and do new things with baseball numbers. My latest foray into such time wasting centered on the never ending spring of Derek Jeter's career arc. To try to get a grip on it, I plotted his career WAR and wRC+ vs. his age and added a second order trendline.
My conclusion: There is no discernible pattern to Derek Jeter's career, and I am thoroughly confused.
Pretty pictures post-jump
Ok, here they are (If the graphs are cut off, switch to the Wide setting [pause], or right click -> view image):
The hell is that? Jeter's WAR graph looks like someone was throwing darts at the paper, and the wRC+ graph isn't much closer to any type of good correlation (denoted by very small values of R2). While some of this can be attributed to measuring the noise related to UZR over a single season, there is a big difference in production between a good Jeter season and a bad Jeter season. Strangest of all, some of Jeter's worst seasons are in what would be considered the prime of his career, while most of his best were in his mid twenties and mid thirties. I don't have much in the way of answers, but I do have some thoughts:
I never really thought of Derek Jeter as an inconsistent player, but he has had some truly excellent seasons and some (comparatively) pedestrian seasons. But, something that is also interesting to me is that however painful his 2010 season was, it wasn't really that much worse than some of the seasons he had in his late twenties.
Also, when I look at the whole context of his career, I don't really see a huge dive off of a cliff, I see the decline as more gradual. I think that a lot of this perception was caused by how much better Jeter was in 2009 than 2010, giving the illusion that it was all gone in a single season. At 37, I don't think he's got any more 2009s in him, but I don't think we can rule out a few more points above the trendline.
I just wish he'd stop being so damn stubborn and let Kevin Long help him get there.
[This means absolutely nothing, but for the sake of the exercise, if you plug 37 into the trendline formulae, it predicts a 92 wRC+ and 3.3 WAR for Jeter in 2011]