Happ’s Plate Discipline Improvements Suggest Potential at Leadoff

Ian Happ is going to dig in as the Cubs leadoff hitter many times to start the year, says Joe Maddon. That’s a little weird on the surface, since Happ’s plate discipline portfolio doesn’t scream “You Go, We Go” like Dexter Fowler’s did. Nope, not at all. Happ had a 31.5 percent outside the zone swing rate (O-swing) last year, which is about 5 percent higher than the league average and nearly 50 percent more than Fowler’s rate.

Except looking at the total numbers can sometimes be misleading. Happ looked more comfortable as he stepped into the batter’s box as last season progressed and the stats bear that out. By September of 2017, his O-swing rate was 20 percent less than it was during his first month with the Cubs.

When the switching-hitting rookie debuted in St. Louis last season, adjusting to the best pitchers in the world led to a 36 percent O-swing rate. Slowly but surely, Happ started taking more pitches and actually began to look kinda-sorta like a relatively patient leadoff guy.

Happ did, however, have to adjust after August, when pitchers were making him expand his zone to the tune of a 33.3 percent O-swing rate. But the rookie fought back right away and posted a 29 percent o-swing — nearly a full point better than league average — in September.

All of this is to say that Happ has it in him to adjust to what he’s seeing and to take pitches. The plate discipline numbers we’re talking about here stabilize rapidly, so we can feel pretty confident in what we see above. For example, one month of O-swing data is more than enough to prove that a player’s talent was more than 50 percent responsible for his plate discipline. So Happ’s encouraging September O-swing numbers aren’t just an artifact of small sample size.

All things considered, Happ is projected to have a .341 wOBA this season with a 9 percent walk rate. Other teams wish they had a leadoff hitter who could put those numbers up. And it’s possible that Happ’s plate discipline numbers continue to get better because he has shown the ability to rapidly adjust when pitchers change things up on him.

And maybe he can keep hitting leadoff home runs, since that works pretty well too.