It endured the entire length of the 2016 season, which is also the entire length of Heyward's Cubs tenure. So yeah, 'chronic'.
And yet,
somehow, Heyward posted a positive wRC+ in five of his six previous seasons. I mean, throwing out 85.7% of Heyward's career sample size because his uniforms happened to be dyed a different color seems like a
totally valid methodology here for determining what a "chronic" problem is. Some people might suggest that, for example, Jon Lester's throwing issues, which have plagued him since high school and persist no matter what shade of uniform he happens to be wearing, represent a truly "chronic" problem. I suppose YMMV, but really, your screed would be on firmer rational footing if you argued that Gary Pressy was jabbing a voodoo doll from behind the organ every time Heyward came to bat, or that Yosh Kawano was sneaking back into the clubhouse in disguise every day to sprinkle anti-hit juju powder inside Heyward's pants.
I also don't think you understand how significantly bad a 72 wRC+ is.
Jason Heyward was the fourth-worst offensive player in terms of wRC+ in all of MLB last year, among qualifying players. It was the 44th worst single-season wRC+ in the last ten years, and certainly much worse than that if I felt like limiting the sample to just outfielders. He created 28% fewer runs than the average player, adjusted for park factors, during 2016. I think that's a rather objective understanding of how awful Heyward was offensively last year. Not sure how I'm misunderstanding things here just because I noted that Heyward has been "not bad" for pretty much the entirety of the rest of his career.
Its not like Heyward got unlucky with 'loud outs', his performance took a slight dip, and things will assuredly be back to normal in 2017. I'm not optimistic about Heyward this year. Watching the 'new swing' in spring training, its like he's made all these load phase adjustments and then reverts back to tightening up, dropping his hands and not getting full extension when he's about to make contact.
His new swing doesn't look natural. It's like he's fighting his own body, and he probably is in a sense. Still, there's a history of performance that indicates Heyward is a pretty good baseball player, and regression is a powerful thing. It certainly seems to me that "regression" seems like a more likely scenario for 2017 than "Jason Heyward forgot how to hit a baseball at age 26 after donning a Cubs uniform for the first time." Is that a controversial position? I had
no idea.
But unlike everyone else here, I'm don't have MLB experience as a player and/or coach...I am only commenting on what I see.
Indeed, these are tough times; someone criticized a post you made on the internet. Chin up, buck-o. Stiff upper lip and all that. Maybe have some ice cream on the couch tonight and then a good cry. You'll get through this.