That’s on the advice of former United midfielder Kleberson.
The Red Devils have been tipped to launch a big-money move for Leicester play-maker Maddison, who has shone for the Foxes this season and last.
United are short of creativity in the final third – a problem that Maddison, who is surely set to become a full England international this season, would help to solve.
Yet Brazilian Kleberson, renowned for failing to make an impact at United despite helping his country to the World Cup the year before he joined, thinks otherwise.
He believes Ed Woodward, United’s executive vice-chairman and chief of transfers, should avoid paying Leicester a big sum for the 22-year-old as they did for Harry Maguire, who swapped the King Power Stadium for Old Trafford for £80million this summer.
“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.”
However, Kleberson does believe Ole Gunnar Solskjaer’s side would benefit from the presence of out-of-favour Juventus striker Mario Mandzukic.
Express Sport understands United have a verbal agreement in place with the 33-year-old Croatian to bring him in in January.
That is with Solskjaer only having Marcus Rashford and Anthony Martial as his current No 9 options.
Kleberson declared: “When you sign big players like Mandzukic, you can see the impact they bring into the club, not just on the pitch but also off the pitch.
”They bring experience for the young players which helps to improve them as they grow into their careers.”
And Kleberson recommends that United recruit Napoli centre-half Koulibaly, who has established himself as one of the best defenders in Europe in recent seasons.
The Senegal international would likely cost a massive amount of money but the former midfielder – now the coach of the Philadelphia Union Academy in Pennsylvania – is convinced he would be a good option.
“Koulibaly looks athletic and physical which will bring more energy in the defence,” Kleberson continued.
“Maguire is a big name in England, but it would be good for United to look outside of the Premier League to find players who could play for them.”