Storer, 23, reportedly left his assigned hotel to go to a shop on his own despite the German team's bubble-like precautions ahead of the season restart at the end of July.
The men's, women's and development teams were split into groups with a dedicated coach and soigneur, and were not allowed to venture into the outside world.
As a result, Storer has since been asked to leave, though only as a precautionary measure.
"We have applied very strict precautions to our training camp in Kuhtai, Austria," read a statement released by the team.
"We want to limit interaction with the outside world as much as possible to minimise the risk of infection of the various bubbles – not only to not get infected but minimise the risks of bringing the virus to the peloton when we return to competition on August 1.
"It's purely as a precaution and Michael himself fully understands it. Top-level sport in 'corona' times is a new situation for everyone.
"A lot is demanded of people and of course we also understand that riders and staff have to get used to this."
Sunweb's respective squads are scheduled to return to racing at the Strade Bianche on August 1.