The Bulgaria international defender is struggling with a groin injury so Michael Morrison is on standby to partner Liverpool loanee Jack Hobbs at centre-half.
Midfielder Aman Verma is eligible after joining the Foxes on a short-term deal on Thursday.
Nigel Pearson reported a sickness bug going around the Walkers Stadium this week but he would not reveal which members of his squad had been affected.
Fit-again trio Danny Livesey, Peter Murphy and Richard Keogh are battling for a spot in Carlisle's defence.
Midfielder Simon Hackney (calf) faces a fitness test while Sunderland's Graham Kavanagh plays his final loan game.