Paris - Paris Saint-Germain talisman Neymar suffered a fresh injury to his right metatarsal in the holders' French Cup win over Strasbourg, the club said Thursday.
A fractured metatarsal curtailed the Brazilian's campaign last season, and the recurrence comes just three weeks ahead of the first leg of PSG's crunch Champions League clash against Manchester United.
Neymar posted a photo of himself leaving the pitch on Instagram, with a caption saying: "Your will be done, my God."
The severity of the new injury is not yet known, although Neymar was able to walk off the field unsupported.
"Initial tests carried out revealed a painful reactivation of the injury to the fifth metatarsal," a club statement said Thursday.
"The treatment will depend on progress over the coming days," it said, adding all medical options would be considered.
Neymar initially tried to continue playing. But he covered his eyes -- in tears, according to witnesses -- as he was forced off to be replaced by Moussa Diaby just after the hour mark.
His early departure was a worrying moment for PSG, with the world's most expensive player having missed the final three months of last season after breaking the same bone.
Each season PSG are judged according to their Champions League results, with former coach Unai Emery sacked following a last-16 loss to eventual champions Real Madrid last term.
Current boss Thomas Tuchel said after the game: "The doctor is worried, 'Ney' is worried, because it is the same foot, the same place."
"It was a situation where he was fouled three times, one after the other. The referee didn't give anything. He twisted his foot."
The PSG coach was also unhappy with suggestions from the Strasbourg players and coach that Neymar had provoked the injury by winding up his opponents.
"It's Neymar's style, but don't come and complain when you get kicked," Strasbourg's Anthony Goncalves told broadcaster Eurosport.
"He is a great player, I respect him. He can enjoy himself but don't come blubbering afterwards."
Neymar's compatriot and PSG teammate Dani Alves claimed that the referee was too passive, urging officials to "protect these kinds of players, because they're the ones who make people pay to come to the stadium".
PSG visit Old Trafford in the last-16 first leg on February 12, before hosting Ole Gunnar Solskjaer's rejuvenated Man United side in the return game on March 6.
Edinson Cavani and Angel Di Maria got the goals on a bitterly cold night at the Parc des Princes as PSG ran out 2-0 winners to reach the last 16.
Tuchel had left out the ill Kylian Mbappe for this game, with Eric Maxim Choupo-Moting handed a rare start in place of the superstar France forward.
The Cameroon international set up Cavani for the fourth-minute opener, before Di Maria -- who had earlier hit the post -- finished into the roof of the net 10 minutes from time as PSG stayed on track to win the French Cup for the fifth season running.
Before kick-off, fans applauded and chanted the name of Emiliano Sala, the former Nantes striker who is feared dead after the plane he was travelling in disappeared over the Channel Islands on Monday as he was on his way to join his new club Cardiff City.