The former Benfica star faces a spell on the sidelines after picking up an ankle injury in the win over Rayo Vallecano
The Portugal international picked up the knock in Madrid's 3-2 Liga win over Rayo Vallecano and was forced to leave the pitch in the dying minutes of the first half of the encounter.
The 25-year-old underwent further examination at the weekend to determine the extent of the injury and Madrid have now announced that Coentrao will be out of action for a while.
"After tests carried out on Fabio Coentrao at the Sanitas La Moraleja Hospital, it has been confirmed that he has a sprained left ankle, which will continue to be monitored," a statement on the club's official website reads.
Coentrao's absence means that Marcelo is likely to be reinstated at left-back for Tuesday's match in Turin after he was rested for the game against Rayo.
Madrid currently sit atop of Group B with nine points from three games and will qualify for the knockout stages with a win over Juve.