Preparing ...Rfa7 with an attack on the a3-pawn before White manages to defend it.
  The depressing 2.Nd2 Rfa7 3.Nb1 can be met by 3...e5!  , opening the position for the bishops; e.g. 4.dxe5 Bxe5  with a huge advantage.
  3.Nb3? Nf5 the queen can't protect the e3-pawn due to the discovered attacks.