I’ll openly admit that I didn’t think Ian Happ would turn around his season so quickly. After all, the Cubs’ sophomore finished April with a .306 wOBA and a meager 6.8 percent walk rate while basically whiffing once every other pitch. But ever since April ended, the switch-hitter has looked like a completely different player en route to a .396 wOBA in May.
Happ’s successful adjustments led to a remarkable improvement in plate discipline. I’m talking about a complete 180-degree change here, folks. Whereas Happ swung at ~35 percent pitches outside the strike-zone as a rookie and throughout this April, he essentially cut down that aggressive rate in half. Happ’s O-Swing rate — swings at pitches outside the zone divided by pitches outside the zone — was only 16 percent during the last three weeks of games. That’s one heck of an improvement.