The 19-year-old is a free agent and can join Pompey outside of the transfer window.
Redknapp said: “We are still trying to get Hyland a work permit. He’s a very good young player.
“We’ve had him over for training and seen a lot of him to know what he’s all about. I think he can be a good player here.
“It has gone on for quite a while, which is a bit frustrating. It’s just about getting that work permit and then we can get him down here.
“We’ll just have to wait and see what happens.”
