Dunne limped out of Saturday's 1-1 home draw with Bolton at half-time with a knee injury. The Republic Of Ireland international now faces a race to be available for Wednesday's Carling Cup tie with Blackburn at Villa Park.
Kevin MacDonald, who has been caretaker boss for the opening seven games of the season following the resignation of Martin O'Neill, said: "Richard got a bang on the knee last Monday and did well to actually play against Bolton.
"It's too early to say whether he'll be fit for Wednesday."
Winger Stewart Downing suffered a gashed shin against Bolton but is expected to be fit for the third-round encounter - a repeat of last season's epic semi-final between the two clubs.
MacDonald said: "Stewart has a bad gash on his shin but he's fine."