The former Benfica fullback has rarely been used in his favoured position this season.
Mourinho explained: "What's important is that Coentrao has recovered and is an option for us.
"Fabio was signed for his versatility. He can play in any position and is an important player for the balance of this team. I don't think he'll be a starter in every game, but I do believe he will be important in all of them."