Brain fog and similar cognitive issues are pretty well documented effects in many cases
It’s an assumption with ample evidence. He’s been improving steadily over the course of years and just totally fell off after having a virus that is known to have lingering effects in many cases. No player ever says anything specific is an issue, sickness, family trouble, relationship issues, etc but they’re human and have problems with all of these things. It’s not stuff they talk about or point to as excuses.
TDA was the third best player at his position and he was scratched for making a hot headed mistake. Mika doesn’t need to have it beat into his head that he’s not playing well, he knows and has said as much. He needs to get out of it and imo bigish minutes with other dangerous players is the best bet for that.
We've never seen a player surging to new career heights and then having a dismal and ineffective season before COVID?
Moreover, if it's long-term COVID then why would continuing to play him help him improve? Wouldn't it be better to confer with doctors and take time away from professional sports?
I'm not saying it isn't COVID, but all we know about Mika is that he tested positive and had to miss training camp. All reports--from he and the team--state that he felt better each day as he returned to play and that there haven't been lingering effects. He's been terrible this year. It could be COVID aftereffects. It could be missing training camp. It could be another injury. It could be concussions catching up to him. It could be mercury is in retrograde. All I know is that what's happening isn't working and something's gotta give. If he's really still sick, then all the more reason to stop playing him at all, let alone as your all situations 1C.