Billy Butler, Canary in the Green and Gold Mine

English: French explanation of the baseball strike zone (Photo credit: Wikipedia)

from 538

The strike zone is (or was?) dropping

Offensive numbers are falling for a number of reasons, but none contributes more than a strike zone whose bottom edge is sinking lower and lower. Since at least the introduction of a PitchF/X grading system in 2009, umpires have been calling a larger and lower strike zone. Pitchers noticed, and have thrown an ever-greater proportion of their pitches at knee height. Meanwhile, the league’s hitters have been reduced to feebly hacking at low balls and producing an endless string of ignominious groundouts.

But a curious thing happened in the second half of last season: After years of sustained decline, the average pitch height bottomed out at about 2.25 feet. Soon after, during the playoffs, average pitch height suddenly rose to a place it hadn’t been since 2011. It was too drastic an increase to be the result of chance alone, and an analysis of ball/strike decisionsconfirmed that umpires were calling pitches in an unusually old-fashioned manner.

Was this a playoff aberration, or the beginning of a correction? Keep an eye on Billy Butler to find out. Despite his entertaining playoff run last year, Butler struggled in the regular season, notching a -0.6 WAR, about equal to what some triple-A replacements might do. Part of his woeful hitting was due to his performance in the bottom third of the strike zone, where he hit .278/.307/.394 and grounded into 12 double plays. Butler is uniquely harmed by the low strike zone because of his poor plate discipline and sluggish speed, which turns most grounders into outs.

If the low strike evaporates, Butler may see his fortunes turn (this is a scenario Oakland A’s general manager Billy Beane, who signed Butler to a contract in the offseason, may be banking on). Balls higher in the strike zone can be more easily turned into flies, and that is where Butler does his damage (he slugged .472 on fly balls). If you don’t want to dive into a trove of Pitch F/X data, Butler’s early season production can serve as a barometer of the strike zone instead: If he’s launching balls high into the outfield, the strike zone may be rising. If he’s attempting to leg out infield singles to poor effect, the zone may still be at its low point.

So far this year, spring training has seen an average pitch height of 2.29 feet,² lower than the playoff spike but higher than it was at any time in 2014.