The teenager enjoyed a successful loan spell with the Championship club this season, making 31 appearances before injury cut short his stay.
Millen told the Evening Post: "I'd love to have him here next season. Tottenham know my feelings and I'll definitely be talking to them during the close season.
"I'm not sure what plans they have for Steven but I've already told them I'm interested if he is available. We'll wait and see in the summer. He's not going to be fit until July anyway, so it's not one I will get an answer on straight away."
Millen added: "Ideally, I would like to get my business done quickly so I can work with new players during pre-season. But that is not always possible and I'm prepared to be patient."