Derby defender Martin Albrechtsen could undergo groin surgery during the international break.
The 28-year-old, a free summer signing from West Brom, has been suffering with a persistent groin injury and has seen a specialist about the problem.
A scan revealed no tear but the problem could take another 10 days to clear up, putting the Dane's availability in doubt when the Championship programme resumes on October 18 with a home game against Plymouth.
Rams boss Paul Jewell must decide whether the time is right for Albrechtsen to have a groin operation.
"Martin's hamstring is not too bad but he may well need a groin operation. We will know more this week," said Jewell.
"There is no tear in the hamstring - the scan was clear - but it will be a bit longer before he is back and he has had an ongoing groin problem. So we have got decisions to make but we can make them with a clear head."
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