AC Milan vice-president Adriano Galliani believes the costs involved in piecing together a deal for Kaka make an agreement 'almost impossible'.
Real Madrid have hinted that they would be prepared to part with the Brazil international this summer.
The Primera Liga giants spent big on the former World Player of the Year back in 2009, with a £55million fee reported to have changed hands.
Kaka has, however, struggled to produce the kind of form in Spain which made him a global superstar during his time in Italy.
Real boss Jose Mourinho has opened the door to a summer transfer, as he continues to track Luka Modric, and a return to Milan has been mooted.
The Rossoneri would welcome Kaka's return, as they look to snatch the Serie A title back from Juventus, but concede that they are likely to miss out on any deal.
The transfer fee involved and the salary required to land the Samba star puts Kaka out of their price bracket.
Galliani told Gazzetta dello Sport: "The Kaka operation is objectively very, very difficult. It is almost impossible.
"Costs are high, and he has a very high salary."