Palermo sack Pioli before season starts
Pioli, who led Chievo Verona to 11th place last season before taking over at Palermo in June, becomes Serie A's second coaching casualty of a season yet to kickoff following Roberto Donadoni's exit from Cagliari.
"Youth team coach Devis Mangia will now take temporary charge," read a statement on the club website.
Palermo, who finished eighth in Serie A last season and reached the final of the Italian Cup, were last week knocked out of the Europa League on the away goals rule by Swiss outfit Thun.
Earlier on Wednesday, Palermo sold Italy midfielder Antonio Nocerino to AC Milan.
He became the latest high-profile departure from the club in the transfer window following Argentine forward Javier Pastore, Italy goalkeeper Salvatore Sirigu and defender Cesare Bovo.
Arriving on transfer deadline day in Palermo were Honduran winger Edgar Alvarez (Bari), Paraguayan midfielder Edgar Barreto (Atalanta) and midfielder Francesco Della Rocca (Bologna).
Last season Palermo dismissed Serse Cosmi after just 36 days in charge.