Leicester later confirmed they had received Mandaric's bid, which is believed to be in the region of £25m.
"My aim is to re-awaken Leicester City and aspire to the dreams of their passionate supporters and bring Premiership football back to the club at the earliest opportunity," said Mandaric.
A statement on the Foxes' website said: "We will give the offer full consideration.
"We have a number of options available to the board and it is imperative that the right decision is taken to safeguard, protect and develop the best interests of the football club in the short, medium and long term.
"As soon as it is practically possible, the club will communicate further with shareholders, supporters and staff."
Mandaric guided Portsmouth into the Premiership before selling the club to Alexandre Gaydamak earlier this year.
He continued in a role of non-executive chairman at Fratton Park before finally severing his links at the end of September.