Fernandes is currently on-loan from Benfica, and Portsmouth has secured an option to buy him.
Redknapp says: “I think he plays X amount of games and then we take up the option to buy him. As far as I know it is a tied-up deal.
“Although he has been out a long time with his injury, people know him here in this country. He played in the Champions League for Benfica last season at Old Trafford. People from there certainly know about him.
“But we’re hoping he will become a top, top player for us – and I’m convinced that will happen.”