Stewart was given his marching orders for a second bookable offence in Monday's disappointing 4-0 defeat at neighbours Walsall and will now serve a one-match suspension, leaving the Sky Blues without a recognised left-back.
Fellow defenders Richard Wood (groin) and Blair Adams (knee) also continue to miss out, as do strikers Leon Clarke (ankle) and Stephen Elliott (knee).
Manager Steven Pressley has plenty to ponder when naming his starting XI having seen an unchanged line-up brushed aside at the Banks's Stadium just four days after beating League One leaders Doncaster.
The likes of Gary McSheffrey, Cody McDonald, Steven Jennings, David Bell, Jordan Clarke and Callum Wilson will all be pushing for starts at the Ricoh Arena.
- Sports & Recreation