Probably Franklin. If team management have no qualms with Franklin playing at six they shouldn't have one with Vettori IMO, especially in Sri Lanka where he's had success with the bat (and ball tbf.)
Blah, blah, blah that isn't fair on Franklin. Since coming back into international cricket as a "batting all rounder" he's been next to hopeless for this team, with bat and especially ball. Averages 21 with a single 50 and a whopping 140 with the ball, offering next to no control either. Dean Brownlie is probably just as much as an all rounder as Franklin is tbh, and I'm kind of being half serious when I say that.
I wouldn't play Patel either tbf, drop him and play the four seamers. Still looks the same Jeetan Patel that averages nigh on 50 to me, and at least with bringing in Wagner we'll have a decent tail. Bracewell, Wagner, Southee, Boult. On most occasions you'll get some pretty decent runs out of that lot.