Man United have yet to agree with Sporting CP over the interest on midfielder Bruno Fernandes, reports said.
The BBC reported valued Fernandes at 60 million pounds ($77.97 million) while Sky Sports said the deal could see United defender Marcos Rojo move the other way.
They have held talks since last year, but this time they are signing for real in January after Paul Pogba suffering from ankle surgery and Scott McTominay nursing a knee injury.
Sporting head coach Silas was unsure if the Fernandes would be available to face Benfica on Jan 17.
“I can’t guarantee any of these things because I don’t know. Bruno is a huge player and all players like him have a lot of market,” he told Sky Sport.
“I don’t like to think about it, but I’ll be thinking of alternatives in case Bruno leaves. I hope it doesn’t happen, but we have to start thinking that.”