Joe Kinnear believes Shay Given wants a new challenge and has admitted the goalkeeper's future is out of his hands.
Given has been strongly linked with a move away from Newcastle during the transfer window despite Kinnear's determination to keep him.
Assistant coach Chris Hughton also insisted earlier this week that the decision to award Steve Harper a new long-term contract did not mean Given would be leaving the club.
However, Kinnear has now hinted that Given could be on his way out of St James' Park, with Manchester City still believed to be interested in the 32-year-old.
"I've bent over backwards to keep Shay, and I have told the powers that be that he has got to stay," Kinnear told the Evening Chronicle.
"But I understand it from Shay's point of view. He wants to leave, but I have tried my hardest to make him stay.
"He's done 11 years here at Newcastle and I think he wants a new challenge.
"I left Shay with Mike Ashley, Derek Llambias and Michael Kennedy, and the talks went on for a few hours.
"It's out of my hands and I am still waiting for the final outcome, but I think he wants a new challenge and that he wants to speak to Manchester City.
"I would be heartbroken to see him go because he is one of the best keepers in the world. But Man City keep banging on the door to talk to him."
Kinnear is keen to bolster his squad over the next week and remains hopeful of pushing through a deal for Toulouse right-back Albin Ebondo.
Habib Beye is set to be sidelined for some time and Newcastle officials have travelled to France in an effort to complete the signing of Ebondo.
Kinnear said: "We are likely to be without Habib Beye for 10 games, and that's 30 points to play for.
"We need more than cover, and we need to build up the squad.
"I'm hopeful Albin will join us and we are just waiting for the handshake on that deal. It's very much an ongoing thing."