Birmingham look set to be without Isaac Vassell when they host Brentford.
The striker is due to undergo a scan on the twisted knee he suffered during the goalless draw with derby rivals Aston Villa on Sunday.
Full-back Carl Jenkinson remains sidelined after shoulder surgery and goalkeeper David Stockdale is still out with an arm injury.
Jota, Harlee Dean and Maxime Colin will all be coming up against the club they left in the summer.
Brentford midfielder Nico Yennaris is likely to miss out after he was knocked unconscious in the 3-2 win over Preston.
Romaine Sawyers and Josh McEachran are among the options to replace the former Arsenal youngster.
Lewis Macleod is on the comeback trail following a knee injury but is probably still a couple of weeks away from full fitness.
Alan Judge (leg) and Rico Henry (knee) remain long-term absentees.