Matri has been poor in the last three matches because of Mirko's absence, it is as simple as that. Matri is the type of striker that needs a second striker to give him the support he needs. Nevertheless, we played the last three games with Pepe and Estigarribia as support for Matri, which was clearly insufficient as neither have the creativity of offensive capabilities to support Matri as Mirko does.
Since Mirko will play next game against Lecce, I expect Matri to have a good game.