I'm guessing that if he has told them he does not want to play there and only has one year left, they might consider something like Smart, 16 and pieces. Maybe you swap AB for Smart.
Seems better than getting nothing and letting him walk next year. And if they do go that route, I'd wait it out if I'm the Celtic. Keep my picks this year, as I don't think they're going to win it all this year, then get Haywood and use your high 17 pick next year.