City chairman John Elsom said "The club has received a written bid from Middlesbrough which we are in broad agreement with, although there are a couple of small matters still to be finalised."
Izzet will begin talks with Boro on his return from international duty with Turkey.
The deal worth £6m will be the second highest transfer that Leicester have received, although they have to pay Chelsea 25% of any profit. Leicester bought him from Chelsea fro £650,000 in 1996.
The highest fee received by Leicester was the £11.5m they received from Liverpool for Emile Heskey.
A final note - don't get too carried away just yet, Boro's recent record of completing transfer is pretty poor.