The Bhoys meet the Spanish giants in their opening Group C match at Camp Nou next Tuesday and could luckily face Luis Enrique's side with Messi on the sidelines.
The Argentine ace aggravated a groin injury in last week's World Cup qualifying win over Uruguay and has returned to Catalonia to receive treatment with his club.
It is understood that he is in doubt for the European clash with Scottish champions Celtic.
A Barcelona statement read: "Tests conducted today on Leo Messi have confirmed that they player is still having trouble with the left adductor muscle.
"He has been recommended to lighten his training load over the next few days and his availability will depend on how the issue progresses."