Good thread, and very difficult to decide. I went with Peterson, but I can argue just a much for siding with Manning. Both had very significant injuries, both of which could have been career ending for other people. While I think Manning's injury was much more serious in terms that had the surgeries not been a success he could have had life-long complications with his neck, and Peterson probably could have lead a fairly normal life with a busted knee, in terms of football playing ability comeback,...I gotta go with AP. He could potentially break Eric Dickerson's single season record less than a year after being in a hospital bed with a ripped up knee.
LET'S GO FLYERS!!!