Sheffield Wednesday skipper Richard Wood could be ruled out until the New Year with a dislocated shoulder.
The defender suffered the injury in the 2-1 defeat to Scunthorpe last week and had to be stretchered from the pitch.
He is to have an explorative operation next Tuesday to discover the full extent of the problem.
If the damage to the shoulder joint is found to be severe, it is likely that he will not be able to return to action until January.
However, if the surgery shows the injury is not as serious as feared Wood could be back later this month.
Under-pressure manager Brian Laws recently lost Francis Jeffers for at least three months with an ankle problem.