Claudio Ranieri has issued Esteban Cambiasso an ultimatum and insisted Leicester need to know if he will stay.
The new Foxes boss has held talks with the midfielder but he is yet to commit his future to the club after his contract expired last month.
Ranieri faced the media for the first time since signing a three-year deal after replacing the axed Nigel Pearson last week and has made keeping Cambiasso a priority.
He managed Cambiasso at Inter Milan between 2011 and 2012 but needs an answer from the former Argentina midfielder.
"I've had a conversation with him. I have spoken to him, I know him from Inter Milan, I coached him there. I said to him 'I need you, everybody loves you in Leicester, please come back'," said Ranieri, who takes the Foxes to Lincoln for a friendly this evening.
"He told me he wants to wait and look at all the opportunities offered to him and then he will choose. But we need 'Yes or No' because at the start of the season he is a team leader and if he doesn't come I need another team leader. We don't start the season without a player like him."
Director of football Jon Rudkin added: "In relation to Esteban, we spoke with him at the end of the season. We're trying very hard to sign him for the next season. Hopefully in the near future we will get answers one way or another.
"We are very hopeful. He is a world-class footballer who is well sought after."