Manchester United fear Rafael da Silva could be forced to go under the knife.
The Daily Mail says United are waiting to see if Rafael needs an operation after the young Brazilian defender dislocated his shoulder for the second time in two years.
Rafael, who dislocated the same joint in July 2009, suffered a recurrence of the injury in training on Thursday but it popped straight back into place.
The 21-year-old has been sent back to the specialist to see if surgery is required and to find out how much of the new season he is likely to miss.
