Brown told Sky Sports News: "He is still connected to a football club, we haven't been given permission by that football club to talk to him, so we will honour that.
"But he will be available from July 1 and hopefully Michael will give us the time of day and we can get around a table, then who knows?"
Brown added: "There's no such thing as a free transfer. It is obviously a very attractive proposition with regard to Hull City.
"To bring, not a former international, a present international, an England international to the club would be a great achievement for myself personally, but for the football club.
"Yes, it is one we are interested in. It isn't a throw-away comment, it is a genuine interest.
"As a free transfer, that would be an interesting prospect for a number of clubs.
"Yes, if we could sit down around a table with Michael and his advisors and maybe draft a deal up that would be workable for both sides, who knows?
"It could be a good start to the transfer market for us."