In short, following this, some observers tried to identify the sequence where Dach suffered his injury. On this subject, see the publications of Patrick Friolet, journalist at RDS:
As the current situation is unclear and forces us to speculate...we are trying to find links to this famous injury that led to "symptoms of illness"
On January 19, Kirby Dach was hit in the right foot by that slap shot from Radko Gudas. He then missed several practices, but continued to play games, until February 14.
This may have been the injury that started it all...
- Patrick Friolet
So here is the video in question:
We shouldn't get into too much speculation, but it could explain a lot. To be continued!