Slovakian Skriniar is one of the names that has been touted as a potential signing for the Red Devils as they look to bolster their backline.
Jose Mourinho missed out on targets Harry Magure, Toby Alderweireld and Jerome Boateng among others in the summer.
And United are expected to ramp up their interest in a central defender once more in January and next summer.
But Calciomercato say Skriniar is stalling on penning fresh terms in Milan due to interest from Old Trafford.
It could take a fee in the region of £60million to get Skriniar out of the San Siro and United would also likely face competition for his signature.
Mourinho was left frustrated by United’s inability to lure a centre-half to the club over the summer and his side have already shipped 14 goals in just eight games so far this term.