Manchester United manager Louis van Gaal has confirmed Bastian Schweinsteiger has suffered a knee injury that is likely rule him out of Tuesday's meeting with Newcastle United.
An injury-time penalty from Wayne Rooney saw United limp into the fourth round of the FA Cup after their unconvincing victory over their League One opponents.
Bastian Schweinsteiger started the match in midfield but was left in agony after coming off the worse in a 50-50 challenge with Sheffield United's Chris Basham. While a stretcher was brought onto the pitch but the Germany international was able to limp off to receive treatment.
With United having already used their three permitted substitutes, Schweinsteiger returned to the pitch to finish the match but still appeared to be in pain.
United have only three days to wait before they return to Premier League action at St James' Park but the 31-year-old midfielder is unlikely to be involved.
"It shall be difficult of course [for Schweinsteiger to face Newcastle]," said van Gaal, United's official website reports. "I don't know yet but I think he has a knee problem. Everyone thinks he has an ankle problem but I think it's more the knee than the ankle. We'll have to wait and see."
The United boss also reassured Morgan Schneiderlin was not injured and that he was merely rested after the busy festive schedule.
"Schneiderlin is not injured but he's in the red zone and had an overload. In the Christmas period, he played every game and we have to take care of that. I don't take risks and, because of that, we have a very young bench. I trust these players also because Pereira is coming in and was a very good substitute, I think.
"With our injuries and players in the red zone, we have to take care of it. I think we have done it well."
United registered just two shots on target during the entire match on another frustrating evening for those in attendance at Old Trafford but Schweinsteiger was pleased with his side's persistence.
"It is always important to fight until the very end," the former Bayern Munich midfielder wrote via Twitter.