If Indy wins they're the 3 and NE is the 4.
If Indy loses, flip them.
EDIT: I just checked the NFL site and if Baltimore, Indy & NE all end up 12-4, the seeding would be: SD, IND, BAL, NE
Indy can be the 2 seed with a win and a Ravens loss. The Pats are definitely locked in to either the 3 or 4.