The problem now with Variety, Hollywood Reporter, and Deadline is that there's a huge competition between the three for scoops, so they'll post anything. Some have weight, coming from the horse's mouth, but half of the time, it's hearsay with no contract work being set up.
A good example is the Viggo scoop from Deadline. I'm sure it was legit, but I don't think it was ever feasible. It's more like WB went to him and he said no due to his commitments to 'Snow White'. Because the internet tends to sensationalize everything, to us it seemed like a big lose while to WB, it's not a big deal.
Michael Shannon might be in the running, but he could be just an actor that Zack wants and he hasn't been approached yet. It's hard to tell. I hope he signs up. As far as I know, he's free (unless Boardwalk Empire starts up again).