Manchester United are increasingly resigned to losing Andre Onana to the Africa Cup of Nations early next year.
The tournament starts in January and finishes in February, meaning United could be left without first-choice keeper Onana for up to six games.
When United signed Onana from Inter Milan for £45million in the summer, the understanding was he would not be returning to the international scene with Cameroon. Onana retired from international football last December, after a row with Cameroon coach Rigobert Song at the World Cup, over the style of play he wanted from his keeper.
But Onana performed a U-turn, returning for Cameroon's final AFCON qualifier against Burundi in September and playing against Senegal last month.
The 27-year-old has been called up for Cameroon's World Cup qualifiers during the current international break, against Mauritius on Friday and Libya next Tuesday.
United have held discussions with Onana about his plans for January and fear they are powerless to stop their first-choice keeper from representing his country early next year.
That would mean a run in the side for United No.2 Altay Bayindir, signed from Fenerbahce for £4.3m in the summer, with the 25-year-old yet to make his debut.
Although Bayindir has yet to play for United, the club's goalkeeping coaches have been hugely impressed by his standard in training since he joined, as has Onana.
Altay Bayindir has not made an appearance for Manchester United yet ( Image: Getty Images)
Onana has told friends Bayindir is the best back-up keeper he has worked with and he knows he may face a battle to reclaim his place as United No.1 if his understudy does well in his absence.
Bayindir has already declared his intention to push Onana for his place and his likely departure to the AFCON is shaping up to be the opportunity the 25-year-old Turkish keeper has been waiting for.
Against that backdrop, Onana is still weighing up whether to make himself available for the AFCON with Cameroon, knowing that decision could ultimately jeopardise his United place.
Although no final decision has been made over Onana and the AFCON, United are understood to be preparing to be without him for several games, with Bayindir primed to replace him.
As well as the Champions League, TNT Sports will also be offering sports fans access to games across the Premier League, Europa League, Serie A and much more. You can also watch the biggest events in boxing, UFC, WWE and get exclusive action from MLB.
Onana endured a difficult start to his United career, with high-profile mistakes against Bayern Munich, Galatasaray and Brentford casting doubt on the decision to recruit him to replace David De Gea.
But Onana has settled down in recent weeks, keeping successive clean sheets in the Premier League and making crucial saves, particularly in Saturday's 1-0 win at home to Luton.
Even though United conceded four goals to lose to Copenhagen in the Champions League last week, the finger of blame was pointed at the defence, rather than Onana, as was the case earlier in the season