Analysts said he might be poised to join the leftwing MDP group, a splinter from the PD, which applauded his move.
PD Deputy Secretary Maurizo Martina said the party „regretted“ Grasso‘s departure.
Anti-establishment 5-Star Movement (M5S) leader Luigi Di Maio said Friday that President Sergio Mattarella should bear in mind Grasso‘s decision when it comes to signing the Rosatellum.
Di Maio added that in the PD „there remain only (leader Matteo) Renzi, the Renzi boys, and (ex-Berlusconi aide Denis) Verdini.“