I'm not that familiar with Ricardo Rodriguez, but a quick look at his positions in his games last year he actually played more often in CB than LB!
This means Montella's experiments last few games where we switch between 3412 and 433 mid game depending on possession are what we'll do next year. Amazing stuff. It worked really well conceptually (we just didn't have the right players).
So this is what we'll probably end up doing:
In possession:
----------Belotti
-----Papu---Suso
Bonaventura--------Conti
---------Biglia--Kessie
------RR--Roma--Musa
While defending:
---------Belotti
Papu------------Suso
-----Bona-----Kessie
----------Biglia
RR--Roma-----Musa--Conti
So basically, Conti will be Montella's new Cuadrado.
Btw, for those not knowing the value of Papu, he's an extremely effect out ball on the left. Very very threatening on the break, and can hold possession to pull players up, even though he's tiny.