Slade could only name five substitutes for the 2-1 defeat at Colchester last weekend and has since seen one of them, striker Shaun Batt, recalled from his loan spell by parent club Millwall.
Winger Lee Cook and forward David Mooney were already missing with knocks and will be assessed.
Skipper Nathan Clarke was Slade's only recognised centre-half in Essex and was partnered by midfielder Romain Vincelot as Scott Cuthbert, Elliot Omozusi and Matheiu Baudry are all injured.
Baudry is closest to returning from a hip injury but Omozusi's shoulder problem is likely to keep him out a while longer and Cuthbert is out for the season with a fractured metatarsal.
- Sports & Recreation
- David Mooney
- Scott Cuthbert
- Shaun Batt