Here's something I found in a quick google search.
https://www.cbssports.com/nhl/news/blue-jackets-ryan-johansen-undergoing-tests-for-illness-fatigue/
So, according to this, it was due to illness. The date of this article was October 25th, 2015. The day after the Colorado game in which he was sent home.
I don't recall anyone calling out his play in 2014-15, especially when he was carrying that team to start the year due to injuries especially with no camp. I do recall 15-16 threads though, but again that was also the season of his heart issue, and thus a conditioning issue. Either way, it's a dead subject now. He's in Nashville thriving, and Jones is here thriving. Both teams are happy.
I do appreciate the way you talk about this issue though, trying to get facts and have a real conversation. With this board and Joey its like talking to a wall who can only say "hurr durr he didn't care lazy team cancer" for a good majority of the posters here.