The kid, who has appeared from nowhere, is on the radar of Manchester City.
The teenager – who opened his Newcastle account in the club’s last game, the 3-3 home draw against Crystal Palace – is facing several weeks on the sidelines.
Aarons’ United form had earned him an England Under-20 call-up.
Alan Pardew: “Unfortunately, he’s picked up a hamstring injury this week.
“He looks a fantastic find for us.
“He was injured on Tuesday, but he hasn’t had a scan yet, so we’ll know more then.”