Inter Milan are understood to be interested in the Armenian, who has been repeatedly dropped by Jose Mourinho. The United boss has been far from impressed with his form this term.
Having failed to start a Premier League game since the defeat at Chelsea on November 5, Mkhitaryan returned with a dismal display in United's goalless draw with Southampton at Old Trafford, fuelling talk of his exit.
Inter Milan were reported to have approached the former Dortmund winger about a potential loan deal on the table, but both Manchester United and the player have flatly refused, according to Sky in Italy.
The Serie A giants, backed by Chinese consortium Suning, have looked into several recruits for the January transfer window, including Gerard Deulofeu at Barcelona and Javier Pastore at Paris Saint Germain.