Colts beat writer Nate Ulrich on Peyton Manning: "Anyone’s expectations had to be readjusted after the second shoe dropped and Manning underwent a third neck procedure in less than 19 months last Thursday. He might return at some point, perhaps mid- to late-December. More likely, he’s out for the season."
Our feeling on Manning is that the Colts aren't going to rush him back if the team is struggling, and the team is going to struggle. He can be safely dropped in all but the deepest redraft leagues. Whether or not keeper/dynasty owners should drop him depends on their league format and keeper rules.