Centre-back Barnett has penned a three-month loan deal from West Brom and could be thrown straight into the mix against a Rams side who have lost eight of their last 11 games.
Captain Stephen Wright missed last weekend's 3-1 defeat to Reading due to flu and has still been struggling this week while fellow central defender Ben Turner had to have an injection in his knee in order to line up at the Ricoh Arena but has also missed some training sessions in recent days.
Both are touch and go for the trip to Pride Park while goalkeeper Keiren Westwood remains a major doubt with the back problem that forced him off against West Brom proving more troublesome than first expected.
Left-back Marcus Hall has returned to training after the death of his father but whether he features remains to be seen.
James McPake and David Bell are both looking for vital match practice following their recent returns from injury while midfielder Sammy Clingan (broken toe) remains on the sidelines.