Michael Stone was not with the Flames at practice today per the organization. He is currently out due to being placed on COVID-19 Protocol. There's no indication if Stone has tested positive, is a close contact, is exhibiting symptoms or just isn't feeling well. The team also hasn't said if this is just a "today" thing and he will be back before the Flames open their regular season on Saturday against the Edmonton Oilers.
Coming into the preseason the all of the Flames players were vaccinated so hopefully this is just something minor for Stone. And not just for the hockey side of it, but for his health as well.