It would not surprise me if there is not any official release until close to kickoff. The best indicator would probably be if Vegas digs into it and ends up dropping the spread by a couple of points. At this point, almost all of the services are hanging around 6 1/2.
If you don't hear anything today, you certainly won't know anything until the Iowa offense takes the field Saturday. Iowa doesn't just let information out, no matter how hard people dig.
You're right about the spread, losing a player of his caliber would change the equation.