That's what any competent AD would do. He either has made up his mind and he's keeping him come hell or high water or he's contingency planning in the background.
Like Kingston says, he probably doesn't have the support ($$$) to do it now. Maybe another loss and a loss to Vandy pushes money people over the edge. Maybe Pruitt wants out, he seems miserable and he may be willing to negotiate the buyout down a bit as his brand is getting tarnished with each pathetic performance. Remember he's a defensive guru and this(his) defense sucks. If he ever wants to be a head coach again, he may want to stop the bleeding.
I think Fulmer has either dug in his heels and plans to bring him back or he's working back channels to see who he can get. If it looks like he can land a good coach, he may be able to sell that to the $$$$ people. If he can't line up someone or if the $$$$ people aren't impressed enough to pony up, he'll just ride with him another year.