My husband is deploying and I am wondering what the chances are for being re-routed to Afghanistan?

He is already "mobilized" but is still here in the states. His orders are to Iraq (not sure where) and he is scheduled to leave the states VERY shortly (not sure when exactly he will be getting into Iraq). In light of the new approval for troops to Afghanistan, what are the chances he will be re-routed? Or since his orders started in October will he still go to Iraq? He is aviation, if that makes a difference... a helicopter electrician. Thanks to anyone who can help me out.