Hedwiges Maduro admits he is still waiting to begin negotiations over a new contract.
Ryan Babel, Kenneth Vermeer and Jan Vertonghen have all committed their long-term futures to Ajax, while the club have opened talks with Johnny Heitinga and Edgar Manucharyan.
Maduro's current deal expires in the summer of 2008 but he has yet to hear anything from Ajax about a possible extension.
Agent Rodger Linse explained: "That we have not been invited for contract negotiations is a signal.
"Hedwiges wants to grow to become a major player at Ajax, but it is logical we are now asking ourselves if he has a future in Amsterdam.
"If the club and player breaks up I hope it will be in a good way."
Maduro added: "If nothing changes I believe I will be sold this summer as this fits in with the Ajax strategy."
Maduro has played 52 league games for Ajax and has also made 12 appearances for the Dutch national team.