The attacking midfielder appears surplus to requirements at his current club, and the Brazilian side are keen to lure him back to his native country following the sale of Ganso
The Peixe are in the market for a new attacking midfielder following the departure of Ganso to Sao Paulo, and they see the Real Madrid man as an ideal replacement.
Ramalho realises that it will not be easy to lure the 30-year-old to the Vila Belmiro, but refused to rule out a potential move in the near future.
"Who would have thought that Sao Paulo could pay that kind of money for Ganso? Anything is possible. Kaka is an option, and so are Diego and Robinho," the Santos coach said at a press conference.
"They are three important players. As I said, anything can happen. It is not just an economical question, but we have to take other aspects into account as well. And we have to act quick.
"We have to support the players we already have here, but it would be good to bring in players who can add something to the team."
Kaka appeared to be on his way to AC Milan earlier this summer, but the move eventually fell through as the Serie A giants were unable to meet Madrid's financial demands.