Strikeouts and Leagues and a Historical First
You know who sucks at hitting? Pitchers. Boy, they just really suck. Pretty much always have, probably always will. Sure, every so often, a random pitcher will run into one and blast a dinger out of nowhere. But the same could be said of Munenori Kawasaki (now), and while pitchers aren’t automatic outs, they’re as close as you’re going to get to automatic outs in a regular major-league baseball game. Maybe this calls for a reminder that pitchers only suck relative to big-league position players. They’re better at hitting than us. But their numbers are always deplorable, and we don’t always have to be all fair-like. When a pitcher bats in a rally, you assume that the rally is over.
The designated hitter became a thing in 1973, following various proposals. From that point on, pitchers stopped hitting in the American League, while they continued hitting in the National League. In the previous sentence I have explained the most basic of rules. Thus, NL pitchers faced a lot of pitchers, while AL pitchers didn’t, even after the advent of interleague play. Unsurprisingly, then, since the DH came into existence, NL pitchers have posted a higher strikeout rate than AL pitchers. They’ve posted a higher strikeout rate every single season.