Derby defender Russell Anderson is facing around three weeks on the sidelines with a groin injury he sustained against Birmingham.
The Scottish centre-half suffered a similar injury on the opening day of last season.
And this time around he was forced off after 35 minutes of the 2-1 victory at Pride Park last weekend.
The problem is expected to keep Anderson on the sidelines until the start of next month.
"Russell had a scan on Monday and it looks like two or three weeks, so that will be after the international break," said manager Nigel Clough.