Yes, that was my post. I was trying to provide rationale to how a player's performance/dynamism can drop for reasons other than injury. I don't think people realize just how much effort NHLers put in day in and day out not to mentioned elite NHLers. You hear about it all the time where someone describes how dialed in an elite NHL player is, and what kind of schedule/regime they have. Just recently a player shared Kucherov's routine and was marveling at how dialed in it was. Referencing how Kucherov would do like 10s or 100s of the same drill where the puck was shot around the boards in the offensive zone and Kucherov picked it up off the boards, without delay, in his usual spot.
And I think Pettersson was, and can be, that kind of player. And we saw this when he talked about (I think during his draft year) how he dissected his shot into numerous segments in order to improve upon it. But it is quite possible that as he became accustomed to success in the NHL he started to take his pedal off the gas and started to let slip some of this preparation and drive. And initially, as you mentioned, the results continue and so there is almost a positive feedback to that decision. But the reality is that the player is getting results because of his previous preparation and drive. And then, predictably at some point, but often quite a bit later, the results then start to drop off as well. And this is when the player really enters into a slump. Because they both look to be performing poorly, but also the results are just not there. And of course the player loses his confidence and that compounds the issue.
We then see the player starting working hard and putting in the effort to get out of the slump. And I think you see that with Pettersson to some extent. But the reality is you can't just turn a switch and get back to your peak performance, and it can take a very long time to do so. And we saw this with his last slump years ago where it took him months to get out of.
With all that said, I am not saying that he doesn't have an injury or anything. I am just trying to convey how players as good as Pettersson can drop in performance so much with it not being predominately driven by injury