That's on the advice of former United midfielder Kleberson.
"I don't think it would be great for Maddison to join United," the World Cup winner told US-Bookies.com.
"They [Leicester] have had a good start to the season but when you do a big jump from a smaller club to United, it is mentally tough for these players.
"They have to be able to learn to adapt to play at a big club. It will be interesting to see if they can, but I don't know if he will be a good enough signing for United."