Juventus wing-back Alex Sandro suffered a thigh strain in the Supercoppa Italiana defeat to AC Milan, his club have confirmed.
Alex Sandro had to be replaced by Patrice Evra after 33 minutes in Doha on Friday, in a match Milan won 4-3 on penalties after a 1-1 draw.
He becomes Juve's latest defensive player to be ruled out through injury - Leonardo Bonucci and Dani Alves are also out, while Andrea Barzagli has only recently returned to selection contention after spending six weeks on the sidelines.
The Italian champions have not released a timescale for Alex Sandro's return, but reports in Italy suggest he could miss up to three weeks of action.
"Initial medical tests have shown that Alex Sandro strained the flexor muscles in his right thigh," read Juve's statement.
"The Brazilian full-back's condition will continue to be closely monitored over the coming days."
Juventus do not play again until they host Bologna in Serie A on January 8.