Derby are waiting to discover the extent of the injury that forced Gareth Roberts to be withdrawn against Watford.
Left-back Roberts was substituted during the second half of the 5-1 victory at Pride Park on Saturday because he had a tight hamstring.
The injury is not thought to be anything serious and the 34-year-old is expected to be fully-fit when the Rams resume npower Championship action at Huddersfield on September 15.
Meanwhile, fellow defender Tom Naylor is on his way back from a groin strain and it is hoped he could do some light training this week.
