Johnstone, who was linked to Villa at the weekend in the press, has confirmed his desire to leave Old Trafford to gain further experience.
Steve Bruce could target the highly-rated 23-year-old when the winter transfer window opens with a new goalkeeper thought to be one of his priorities.
Johnstone signed a new two-year-deal with the Red Devils on Sunday and then told his 328,000 Instagram followers that he was looking for a loan move.
One fan asked: "Why don't you go on loan and get game time mate...You're a good keeper with great potential."
And Johnstone replied by saying: "That's exactly what I want to do."