The youngster said; "It was a great experience and I learned what is demanded of me at this level.
"They didn't point out the things that I was weak on, but focused on what I'm good at, like I have a good right foot and high pace."
Keegan is now going to monitor his form with a view to bringing him to Manchester when the Norwegian season ends in November.
A permanent deal would be difficult at present due to work permit requirements but the teenager has applied for Norwegian citizenship, which should smooth the way.