Cagliari President Massimo Cellino has given Milan the green light to sign Andrea Lazzari.
The 26-year-old is Max Allegri's No 1 choice to reinforce his midfield in Janury.
Lazzari worked with Allegri for two years in Sardinia and has a close bond with the Milan boss.
"There is a willingness to negotiate," Cellino said.
"However in my opinion there won't be any particular problems seeing the relationship that I have with a true friend like Milan Vice-President Adriano Galliani.
"If Milan and Lazzari want [the move], then there is no problem. But we need an adequate compensation."