After an impressive season with Bologna, helping them secure Champions League qualification, Ndoye has taken that form into the Euros with Switzerland.
The wing-back has caught the eye of United scouts and Sky Italia's Gianluca di Marzio is reporting an enquiry has been lodged over the past 24 hours.
Interestingly, Ndoye is a former Nice and Lausanne player - two clubs United director Sir Jim Ratcliffe owns.
Just yesterday, the Swiss' agent Lodovico Spinosi told TV Play: "I can tell you that he is being watched not only by Italian teams, but also by foreign ones.
"The good thing is that he is in a club like Bologna, super healthy, that will play in the Champions League. To date there is nothing concrete except expressions of interest.
