The Chelsea striker was told by manager Antonio Conte last week that he is not in his plans for next season, despite scoring 22 goals last term.
Costa open to Atletico return
Speaking to Sky Sport Italia about the €38 million transfer of Andre Silva to AC Milan, Mendes also mentioned Costa but refused to go into finer detail about a potential move.
Mendes said: “Diego Costa to Milan? What I talk to Milan about, I won’t tell the press…”
The Spain international recently ruled out a move to China, amidst rumours Tianjin Quanjin would come back in for him after they had a big-money bid rejected in January.
