Derby boss Nigel Clough expects to be without the services of Jamie Ward when the Rams make the trip to league leaders Cardiff on Tuesday night.
The striker limped out of last Friday's defeat to Crystal Palace after picking up a hamstring injury.
Ward, who missed three months of the season with a similar problem, was due to undergo an MRI on Monday to assess the full extent of the injury.
Midfielder Michael Jacobs replaced him on the day and could deputise again, while strikers Conor Doyle and Mason Bennett provide further options should Clough wish to stick with his favoured 4-3-3 formation.
Ben Davies could return to the starting XI after settling for a place on the bench against the Eagles with a groin complaint.
Teenage midfielder Will Hughes remains sidelined with a similar problem while Kieron Freeman (ankle) and James O'Connor (knee) are also doubtful.
Cardiff manager Malky Mackay has a dilemma at the heart of his defence. Mark Hudson's ankle injury meant he missed the defeat at Middlesbrough and the centre-back will be sidelined once more when the Rams arrive in Wales.
Mackay now has to decide whether to select the same back four that conceded two in a forgettable first half, with Matthew Connolly partnering Ben Turner in the centre-back positions, or recall youngster Ben Nugent alongside the former Coventry man with Connolly returning to the right-back slot he has made his own in recent weeks.
Nugent was introduced at half-time at The Riverside and his performance was praised by his Scottish manager after the match.
Cardiff have lost the last two matches Hudson has missed and defeat to Boro means they have now lost two of their last three Championship clashes.