Manchester United have invited Livingston's teenage striker Matthew Knox for a third trial next week.
The 17-year-old striker last visited Carrington in August and has also paid visits to Liverpool, Tottenham, Everton and Nottingham Forest.
He became the club's youngest ever player at 16 on Boxing Day last year and has made seven appearances for the Scottish third tier side this season.
Rangers made a £75,000 bid for him in the summer, but the Scottish League One side rejected the offer.