I'm on Indy -7 with Portis out. Couldn't find -6.5 at any of my books, unfortunately.
I think Indy wins by over 17 points with Portis out. Maybe I'm under-estimating Denver w/o Portis, but I think Portis doesn't get enough credit for carrying this Denver team, regardless of how good the Oline is supposed to be. Respect for Anderson but he doesn't have explosiveness of Portis. Without the explosiveness to break into secondary, there is less risk for stacking the line to stop run.