Raphael Varane was forced off with an injury during the Nations League final between France and Spain on Sunday.
Varane stretched to clear a cross from the right flank in the 40th minute and was taken off moments later after going down to receive medical treatment.
The extent of the centre-back's injury and the exact nature of the problem remained unclear from what seemed like an innocuous situation, with Dayot Upamecano immediately introduced by Didier Deschamps.
Up until his injury, Varane had won only one of three duels but made a team-high two clearances as France limited Spain to speculative efforts.
The former Real Madrid defender's knock will offer Manchester United potential cause for concern as, depending on the extent of the injury, the 28-year-old could be a doubt for next week's Premier League match against Leicester City.
Ole Gunnar Solskjaer's side also have a Champions League clash with Atalanta to contend with before a huge meeting with rivals Liverpool, with Tottenham following on October 30.
United already had injury problems at the back, too, with Harry Maguire having missed time before the international break due to a calf problem.