AC Milan chairman Marco Fassone has revealed that he has spoken with Diego Costa's agent Jorge Mendes.
Costa, who recently uploaded a video to his Instagram account of himself doing some improvised training on a Brazilian beach, was omitted from Chelsea's pre-season tour of Asia by Blues boss Antonio Conte.
When asked about the former Atletico Madrid forward, Fassone told Sky Sports: "I would prefer to avoid talking about players from other teams; Diego Costa is a great player, but a Chelsea player.
"We went to see Jorge Mendes; there is a lot you can talk to him about. Costa is a great player but he is of Chelsea. That's all."
The Brazil- born Spain international was told that he would not be in Conte's plans for next season via a text message at the end of last season.
Conte has since replaced the 28-year-old with the £70m signing of Alvaro Morata from Real Madrid.
The two-time Premier League winner, who has scored 58 goals since arriving at Stamford Bridge, is reportedly interested in returning to former club Atletico Madrid, but the Spanish club's transfer ban prevents them from making any signing until January.