BBC Sport reports that a source at the federation said: "[Hiddink] can't say no to Chelsea, we believe he wants to leave".
Turkish Football Federation president Mahmut Ozgener, is likely to be replaced when the organisation holds elections on 28 June.
"If Ozgener was staying, Guus would probably stay too," said the BBC's source. "Ozgener has gone on holiday and hasn't decided if he will stand for re-election, but even if does he's likely to lose.
"Hiddink says he has a contract but these promises don't have value.
"Chelsea is too good an offer to turn down and the Federation understands this.
"Hiddink feels he still has a job to do there, he wants to work every day, and win Championships and maybe the Champions League.
"We will understand that he has coached his last Turkey game as long as Chelsea pay the compensation."