Brentford have been assessing captain John Egan in the build-up to Tuesday's Sky Bet Championship home clash with Derby.
The defender went off early on in the 3-0 win at Bolton on Saturday having sustained a head injury.
The Bees are set to once again be without Sergi Canos and Lasse Vibe, who have been sidelined by ankle and foot problems respectively.
And Lewis Macleod is not yet ready for a return to action as he continues his recovery from a knee injury.
Derby are monitoring Tom Lawrence and Curtis Davies ahead of the trip to Griffin Park.
Midfielder Lawrence complained of a tight groin during the home draw with Birmingham while centre-half Davies has been managing a similar problem recently.
Johnny Russell was fit but was left out of the squad on Saturday, although Rams boss Gary Rowett would not say why at his pre-match press conference on Monday morning. It remains to be seen if the forward will be involved on Tuesday.
Midfielder George Thorne was ill at the weekend and Rowett has yet to decide if he will return to the squad.