The trail from the batter's box back to the dugout is getting more worn down by the day. The rate of hitters striking out is exploding. Twenty years ago, barely 15 percent of at-bats ended in strikeouts. Ten years ago, it was 16.4 percent. Five years ago, less than 18 percent of at-bats ended in strikeouts. So far this year, it's up to 20 percent — almost a strikeout every half-inning.