And Given believes that with Johnstone now experiencing regular first team football at Villa Park, he may want to turn his loan move into a permanent deal in January.
"Well, I think that would be good if they could keep him," Given told Express Sport. "He's had a great season.
"I don't know what Manchester United will be thinking about that.
"But Sam will have a taste for playing at Aston Villa now as well and I wouldn't imagine he'd want to go back and play Under-23s or whatever at Man United.
"He'll want to further his career and, I can't speak for Sam of course, but I'm sure Villa would love to keep him."