The club had announced they were signing the Italian, who left Juventus this summer.
“This is huge for Sydney FC, huge for the A-League and huge for Australian football,” Sydney FC chairman Scott Barlow said.
“We feel honoured that Alessandro has decided to play for Sydney FC and we share his excitement that a move to Sydney FC will create a lasting legacy for football in this country.
“I want to thank Tony Pignata and Lou Sticca for the outstanding work over the last few days in progressing discussions with Alessandro and look forward to Tony finalising the contract in Italy over the coming days.”
According to Sky Sport Italia, the player is yet to make a final decision.
