After promotion to Serie A, under new manager Ciro Ferrara, Rossini was first-choice centre-back alongside captain Daniele Gastaldello at the heart of the defence. Rossini's first Serie A match was against Milan on 26 August 2012. After the arrival of new manager Delio Rossi, Rossini lost his place in the team after Angelo Palombo returned from Internazionale and was played regularly at centre-back, at Rossini's expense. In total, Rossini made 25 Serie A appearances in the 2012–13 season.