The 23-year old midfielder, who can also play in defence, is out of contract next summer but Di Canio would be loath to lose him and has urged the former Ipswich Town loanee to re-sign.
"Jack is in negotiations but I hope he is going to sign a new contract because it would be difficult for him to find a better club than Sunderland,” said the Italian.
"I know Jack wasn't happy in general at the end of last year and I had a chat and told him I don't want unhappy people here, but he has a big chance this year.
"In my opinion Jack is one of the best few left-backs in the country. He has all the characteristic qualities - he is aggressive, tough and intelligent and he can push forward.
"It depends on him but I'm very satisfied with the way he played in the last few games. He deserves a new contract and he can have a very good future here."