United have largely played both players on the right wing this season.
But the Manchester Evening News says the club see their futures elsewhere on the field of play.
Regarding James, it's said that he could be played on the left wing instead in the coming years.
And that's because it's the Wales international's favoured position, despite his impressive displays on the opposite flank.
Regarding Greenwood, United see the 18-year-old as a No 9 in the long run.