Birmingham will check on Kristian Pedersen and Gary Gardner ahead of Saturday’s Sky Bet Championship clash with Blackburn at St Andrew’s.
Pedersen came off at half-time in the 4-0 loss to Derby on Tuesday, with Blues boss Aitor Karanka saying the defender had told him he could not play on having taken a kick to the knee.
Karanka also said he thought midfielder Gardner, who was substituted around the hour mark, had suffered a hamstring issue.
Alen Halilovic (groin) sat out the contest, along with Caolan Boyd-Munce (thigh) and Zach Jeacock (ankle).
Four Blackburn players are being assessed following Tuesday’s 2-1 defeat at Huddersfield.
They include three of their starting back four, Ryan Nyambe and Daniel Ayala, who came off in the second half with a tight hamstring and muscle strain respectively, and Darragh Lenihan, whom boss Tony Mowbray said had “soldiered on” to complete the game after a tackle.
The other doubt is midfielder Tom Trybull, substituted in the 11th minute following a clash of knees.
Defenders Derrick Williams (quadriceps) and Scott Wharton (Achilles) are among the players Blackburn already had unavailable, a list that also includes Elliott Bennett, Lewis Travis, Corry Evans and Joe Rankin-Costello.