Cudicini was forced off with a hamstring injury and joins Petr Cech on the sidelines following the first-choice goalkeeper's facial injury sustained in training.
Grant said: "The news is that is doesn't look so good for the moment with Carlo but we need to wait and see. It is his hamstring.
"This year I am more a doctor than a manager, I need to answer every week about injuries."
Hilario came off the bench and he was needed to save from Gokhan Gonul and Colin Kazim-Richards to keep Chelsea ahead on away goals following Ballack's fourth minute header.
The injury means Rhys Taylor, 18 earlier this week, could be on the bench against Wigan on Monday.
Grant added: "Hilario was good today. It is very important for a third goalkeeper when you need him, and we have needed him this year, for him to do a good job. It's not easy when you lose your goalkeeper.
"We Hilario and have the goalkeeper from the youth team. He is a good goalkeeper."