Blackwell is once again struggling to name an 18-man squad due to injuries and suspensions, with skipper Chris Morgan the latest player sidelined.
Morgan sits out a two-game ban after reaching 10 bookings for the season, while Toni Kallio has returned to parent club Fulham due to a calf injury and Kyle Bartley, on loan from Arsenal, is suffering from the after effects of food poisoning.
Nyron Nosworthy, on loan from Sunderland, may switch to centre-half alongside Marcel Seip in Morgan's absence. Fellow defenders Gary Naysmith and Ryan France (both knee) and Derek Geary (ankle) are long-term absentees.
Midfielder Lee Williamson is still doubtful due to the hamstring injury that kept him out of Saturday's 1-1 draw with QPR, and Jamie Ward (hamstring) and Ched Evans (collarbone) also remain sidelined.