Turner left the Black Cats last summer after spending three seasons at the club, where he made 61 appearances.
He told The Mirror: "I had a great first season there, but in my second year I picked up a bad injury. It was a massive setback for me and after that my time there was just completely disrupted by one injury after another.
"I played a few good games for them and we had some big wins. But their supporters never saw the best of me. I definitely don't feel I have anything to prove. But hopefully I can show them that I'm a pretty good player."
Norwich are currently 14th in the Premier League, nine points clear of the relegation zone.