Health related observation
It used to be that players ran off the field and breathed from oxygen tanks so they would be ready for their next series.
Now we see many of them putting on masks instead which means they are getting less ogygen and more carbon dioxide. I would have to imagine that this would negatively affect their perfromance.
Example:
Brady is not wearing a mask on the sidlines while Mahommes is wearing a mask.
So far Brady appears to be performing better than Mahomes.
We'll see how it goes, just a thought.