I believe that we will only go for Vucinic if we fail to sign Aguero.
It wouldn't make sense otherwise since we already have Matri, Quag, Toni, Del Piero, Amauri and Iaquinta. Hopefully, we will manage to sell Amauri and Iaquinta, while Toni and Del Piero will retire at the end of the season.
Aguero, Quag, Matri, Toni and Del Piero is plenty enough for next season.