From SABR member Brian Mills at The Hardball Times on September 8, 2016:
Back in 2014, it became clear that a large portion of the decrease in run scoring during the 2000s drop – as much as 40 percent – could be attributed to umpires expanding their strike zone downward about three inches. This was confirmed by three independent researchers: Jon Roegele here at THT, Ben Lindbergh at Grantland, and yours truly. The trend in the larger strike zone had started around 2009 and continued through 2014. Prior to the 2015 season, Jeff Passan reported it was something the league would look into, particularly if the low-scoring games were less interesting to fans. But, as Jon showed, the strike zone expansion continued as the 2015 season began.
Beginning last August, however, home runs started to increase and offense made a small comeback. In 2016 that trend has continued, and data from MLB’s new Statcast system show exit velocity is to blame: The ball is coming off the bat harder than it was last year. This has been well documented by others.
The increase in exit velocity and home runs has led to various theories about the return of steroids or “juiced” baseballs. These are pretty serious accusations. The former implies impropriety among players. The latter has precedent I’m sure Rob Manfred would prefer to avoid. It cost Ryozo Kato, the commissioner of the Nippon Professional League in Japan, his job.
Read the full article here: http://www.hardballtimes.com/are-the-umpires-at-it-again/
Originally published: September 8, 2016. Last Updated: September 8, 2016.