It's always possible when you're in the playoffs and you have a QB like Brady. I guess it's even theoretically possible that we could pull an '06 Colts and go from worst to first in run defense between the regular season and the playoffs.
But no, realistically I don't think we have a real shot without Gronk. Puncher's chance, nothing more.
If there's one thing working in our favor, it's that nobody in the AFC looks especially good right now. Even Denver has the whole "Peyton in the playoffs" thing going against them.
Man, I'll even forget about everyone else - if Gronk and one of Wilfork/Mayo was healthy, we'd be the favorite to represent the AFC in the Super Bowl.