See, I think this is drawing the wrong conclusions. I mean I agree with what you're suggesting that essentially his numbers are down since then but I don't agree with the why In fact I'd argue that St. Louis is the reason he is fucked up as a hitter. The thing that stands out to me is the fact 2015 he had a 2.44 GB/FB rate. That isn't good. League average is 1.22. There's some players who can make it work. For example, Yelich is a career 2.88 guy. But typically speaking you want to hit the ball in the air.
As it pertains to Heyward, with the exception of his weird rookie year when he puts the ball in the air he hits the ball harder. If you look at the 3 year "prime" of his career from 2012-2014 in atlanta he was 1.20 , 1.25, and 1.28. You then had that 2.44 year in STL followed by the last three where he's been 1.39, 1.45, and 1.41. However, if you look at the first half of last year he was at 1.13. The second half it went big again at 2.08. First half he hit .285/.344/.431(109 wRC+). Second half he hit .247/.321/.337(82 wRC+). So, I don't think he's peaked as it were. I think there's something that's changed in his swing he's trying to get back to. Basically, if he hits the ball in the air good things happen for him. And even with that bad second half he still posted the third hardest hit rate of his career at 29.7%. Only two better years were that weird 2010 at 38.8% and then 2012 at 34.5%.
