Mains: New Year’s resolutions: pitchers’ plate discipline

From SABR member Rob Mains at Baseball Prospectus on January 19, 2017:

In this series, we’re investigating the outcomes when baseball players made what appear to have been New Year’s resolutions to do something differently in 2016. But unlike the rest of us, who resolve to get a new job or limit the time we spend on Facebook, we’re looking here at specific baseball outcomes.

The first article considered batters who hit markedly more (or less) to the opposite field in 2016 than in 2015. The next two looked at batters who hit more or fewer balls on the ground and pitchers who induced more or fewer grounders. The most recent article looked at hitters who improved their plate discipline. Next, let’s check out pitchers’ plate discipline.

As I explained in the last article, there’s a problem with defining plate discipline. For hitters, we can look at how frequently a batter swings at pitches in the strike zone (Z-Swing %) and avoids swinging at pitches outside the strike zone (O-Swing %) as indicators of plate discipline. The opposite is true of pitchers, as it would seem that the best pitchers fool batters into not swinging at strikes and get hitters to chase pitches outside the zone. But neither is a perfect measure.

Read the full article here:

Originally published: January 19, 2017. Last Updated: January 19, 2017.