Di Canio says Sunderland must remain upbeat and concentrate on getting the points they need to secure survival instead of worrying about their lengthy list of absentees.
He said: "It is obvious Craig is a key player. He is one of the fighters on the field. He is one of the leaders of the team with the way he plays. He leads by example.
"However, we do not have time to cry. We must keep the positive energy around us. We lost Danny Graham for the game on Sunday too.
"However, the most important thing is to remain positive because we have enough players to get through this spell and get results."