The Derby centre-back sustained a hamstring injury in Saturday's 2-0 defeat at Sheffield Wednesday so Matt Lawrence, who replaced Davis after 56 minutes at Hillsborough, is likely to deputise.
Winger Paul Ifill has been struggling with a hamstring problem but could feature against the Blues but defender Paddy McCarthy (shoulder) is not expected to return to action until mid-March.
Australian midfielder Nick Carle is again expected to be included in the squad after returning from suspension to be an unused substitute at the weekend.
Birmingham are sweating on the fitness of captain Lee Carsley.
The tenacious midfielder, who has started every league and cup game for Blues so far this season, had to leave the pitch after just half-an-hour of Saturday's 1-0 defeat against Coventry with a neck problem.
Experienced defender Stephen Carr should be eligible to make his debut at right-back having penned a one-month deal.
But the promotion hopefuls will be without leading goalscorer Kevin Phillips (hamstring) and fellow forwards Garry O'Connor (groin) and James McFadden (knee).
Right-back Stuart Parnaby (thigh) and midfielder Kemy Agustien (groin) also remain sidelined as manager Alex McLeish ponders changes following the loss at the Ricoh Arena.
"I'll now consider shuffling the pack with Crystal Palace on Tuesday in mind," he told the club's official website. "I have players sat on the bench and in the squad who must now be thinking they should have a chance."
Sporting Life