22 February 2009

Different Kind of Ball

A Different Kind of Ball
Some may remember a post I wrote on the old Camden Depot site about how much of the Steroid Era was actually caused by steroids. I cited this article which put it quite well:
The URI study showed that baseballs from two well-separated years in the post-1993 era (1995 and 2000) were very like each other, yet very different from balls from pre-1993 years; it also showed significant categorical differences between the older Spalding and newer Rawlings balls. The Penn State study showed a marked increase in zip from 1977 on. All that agrees with the stats-indicated and common-sense indicated belief in a big jump when the ball maker was changed between 1976 and 1977, as well as the belief that there was a subsequent jump starting in 1993 and in full force in 1994.

Essentially, the ball changed in 1993 and everything changed at that point. Power rose significantly and team composition changed with it.

A second article came out recently, which falls in line with the studies on baseball density. They focuses on slugging percentage on contact and presented this convenient chart:

It is pretty impressive how all of this information keeps on validating each other. One of the problems with this belief in steroids is that the power change came with such an immediate effect. That just does not follow drug use patterns. Baseball players simply did not all start taking steroids prior to the 1993 season. It then makes sense that a comprehensive event has to happen. That typically means expansion or perhaps a new baseball. I also find it hard to believe that most ball players knew exactly how to use steroids in order to increase their performance. It is not like there is a lot of scientific information sharing regarding steroid use and baseball performance to go about. It seems most of the usage and planning was based on word of mouth and a few gym rats.

Slap Hitters Are Thrown Fastballs
FanGraphs put out an interesting little exercise comparing isolated power with the percentage of fastballs a player will see. Though the data is noisy, there seems to be a direct relationship between a lack of power and the number of fastballs thrown to a player. Slap hitters are challenged often, which makes sense as you will reduce the number of pitches thrown for that at bat and the probable outcome is a ground ball. The noise is probably explained by variables, such as scouting reports that indicate a hitter may be particularly good or bad at hitting off speed pitches.

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