Rangnick has been handed the reins at Old Trafford on a temporary basis until the summer, while Manchester United conduct the search for a new permanent manager.
The new permanent Manchester United boss is likely to have his own ideas on player recruitment, but Rangnick will be allowed to make signings in the window.
If an opportunity presents itself then Manchester United will let Rangnick add to the squad.
The Red Devils could have outgoings in the window, with Anthony Martial keen to leave to secure regular playing time.
Fellow attacker Edinson Cavani has also been linked with an exit amid interest from South America and Spanish giants Barcelona.
Rangnick’s Manchester United are in action this evening in the Premier League, with a clash against Newcastle United on the agenda.
Victory in the north east would move Manchester United up to fifth, above Tottenham Hotspur.
