Schlupp's trial with the Premier League leaders has been extended but Charlton manager Chris Powell has revealed he could capitalise if United decide not to take their interest further.
"I hope it goes well for him, but if it doesn't there is another team in red that he can always wear the shirt of," said Powell, who became aware of the 20-year-old Ghana international during his time at Leicester.
"We will just have to wait and see on that one. I have kept a close eye on Jeff. He played when I took the development team.
"He played a number of times and you could see him as a player there."