More on David Wright’s streakiness

During the 2010 season, I wondered if David Wright was actually any streakier than any other hitter. I know he has a reputation for ups and downs, but I speculated that perhaps all players endure ups and downs and we just notice Wright’s because he’s the best hitter on the Mets and because we’ve labeled him “streaky.”

Today at Beyond the Boxscore, Bill Petti investigates Wright’s “volatility” by calculating and plotting 10-day moving averages for his WPA (win probability added) from 2005 on. It’s an interesting read with colorful graphs, and using the moving averages seems as good a way as any to try to track consistency. He concludes:

As one would expect, Wright experiences peaks and valleys over the course of the season.  If we look closely, however, we see that Wright does appear to have become both more volatile over the past few years and has experienced an increase in stretches where, on average, he negatively affects the Mets chances of winning games.  Wright’s positive streaks do not last as long and his negative streaks have deepened and last longer.

Wright’s best year was 2007, where he averaged a WPA of .029 (highest since 2005) and had a standard deviation of .032 (second lowest since 2005).   Wright’s lack of volatility coincided with his best overall performance at the plate (OPS+ of 149, offensive Wins Above Replacement of 7.5).  Since 2007 we see an increase in deep negative stretches, with 2009 and 2010 looking especially volatile.  Essentially, Wright has gone from a consistent high-performer to a boom-or-bust type player.

OK, a couple issues here: First, it’s really difficult to determine if Wright is any more volatile than any other baseball player without points of comparison. Petti shows that Wright has endured longer and deeper slumps in 2009 and 2010 than he did in 2007 and 2008, but he doesn’t show how Wright’s peaks and valleys in any season compare with those of similar offensive performers.

And more importantly, it seems like mere common sense that Wright would have endured more slumps in 2009 and 2010 than he did in 2007 and 2008: He wasn’t as good. Wright enjoyed the best offensive season of his career in 2007. Of course he didn’t have as many slumps then as he did in 2009.

Wright’s wOBA has been on a steady decline since 2007, so it seems to me to make perfect sense that he’d also seem to be getting progressively “streakier” in that time. If I had to bet, I’d guess a similar analysis of Ryan Howard would determine he was way more volatile from 2008-2010 than he was in 2006 and 2007.

It’s a chicken-and-egg thing, of course, because you can say, “oh well maybe if Wright were less volatile the last two seasons his stats for the season would have been as good as they were in 2007 and 2008.” And that’s true, but it doesn’t really matter much one way or the other. Without other players for comparison, we have no way of knowing if Wright’s perceived streakiness is something unique to him or just normal fluctuation, an expected function of performance at his 2009 and 2010 levels.

My expectation is — as it was in June — that the only very consistent performers in baseball are the truly excellent (like Wright in 2007) and (to reuse a phrase from yesterday) the downright Rafael Belliard awful.

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