Heart of Midlothian are in talks with United over a move for Ian Cathro.
The Scottish Premiership club want assistant coach Cathro to replace Robbie Neilson, who has taken over as manager of MK Dons.
The 30-year-old would become the youngest manager in the history of Scotland's top tier if he is appointed at Tynecastle.
Cathro started his coaching career at Dundee United under Hearts director of football Craig Levein.
Speaking before Hearts made their approach, Newcastle manager Benitez said: "He is a great young coach with some experience and he has a great future.
“I have no idea (if we'll get an approach). Every is talking about the same. It depends on their head coach at the moment.”