Zimmerman: Do hitters wear down over a season?

From Jeff Zimmerman at The Hardball Times on December 1, 2014:

While watching and listening to games this past postseason, I heard quite a few comments on players wearing down as the season dragged on. The narratives were all over the place. Are the older players able to pace themselves over the season because of experience? Do the younger players have youth on their side and continue producing? Is there a difference? When I went searching for an answer, the results surprised me.

To see how hitters perform as the season wears on, I compared their production in the first half (1H) to the second half (2H). One issue with doing these comparisons is the decline in the offense environment that started after the 2005 ban on performance-enhancing drugs. To help adjust for this drop in offense, I used wRC+, which is adjusted for the league and season run environment. This is not so important with the 1H to 2H comps, but I also compared one year’s second half to the next season’s first half. There, it is more valuable.

First, hitter change in performance from first half to second half.  (There’s a note on my methodology at the end of this article.)

Read the full article here: http://www.hardballtimes.com/do-hitters-wear-down-over-a-season/

Originally published: December 1, 2014. Last Updated: December 1, 2014.