Manchester United have contacted Benfica over the availability of central defender Victor Lindelof, according to reports.
The 22-year-old Swede has played every minute of his side's Champions League campaign so far this season, and missed only one league match due to international duty.
According to Sky Sports News, Benfica have told Jose Mourinho that they will not allow Lindelof to leave the Estadio da Luz if they progress to the last 16 of the Champions League.
The Eagles currently sit top of Group B on eight points, level with Napoli and one point ahead of Besiktas.