Sandro had been expected to be involved in the squads to face both Germany and Russia before the end of the month, but the left-back was forced to withdraw from the double-header.
Juventus have not disclosed how long Sandro will spend on the sidelines, but the Italian giants have moved to confirm the issue picked up by the 27-year-old.
A statement read: "After having returned from the Brazilian national team training camp, Alex Sandro was given further medical examinations, which confirmed the extent of the injury.
"The player has a muscular issue with his right thigh and will begin physiotherapy today."
Sandro has made a total of 28 starts and three substitute outings for Juventus in all competitions this season.