Manchester United boss Jose Mourinho has claimed that Luke Shaw suffered "a big injury" during Sunday's 1-1 draw against Swansea City in the Premier League.
Shaw had to be replaced just nine minutes into the league match, with the England international grimacing as he left the field holding his leg.
There has not yet been an official medical report on the left-back, but Mourinho expects that Shaw has suffered a serious problem due to the fact that the 21-year-old could not continue at such an early stage.
"I don't know about the injuries," Mourinho told BT Sport. "I think Luke Shaw's must be a big injury, because to leave the pitch after 10 minutes I am expecting a very big injury. I prefer not to speak about Phil Jones and Chris Smalling. I prefer to speak about Juan Mata giving everything to be available. I am grateful for that.
"We will give everything on Thursday. That is sure. Whether we go to the final or not doesn't matter, I am really happy with the guys. We lost players and we lost points, so yes today was a bad day.
"We did not look tired and exhausted, we are tired and exhausted. You cannot isolate the performance out of the context. This is the ninth match of April, it is not human. We have a squad of 22 that is reduced to 13 or 14 players. The players are very tired."
Wayne Rooney sent Man United ahead from the penalty spot against Swansea, but a Gylfi Sigurdsson free kick 11 minutes from time saw the points shared at Old Trafford.