Exeter will be without Jordan Moore-Taylor when they host Portsmouth.
The 20-year-old defender, who looked certain to start at St James Park before injury, has suffered a cracked metatarsal and will be the only player who will definitely miss out against Pompey.
Liam Sercombe and Scot Bennett missed the 2-0 defeat to Torquay last Saturday due to a bug while David Wheeler, Arron Davies, Matt Oakley and Pat Baldwin were also affected, but all six look set to declare themselves fit.
Tisdale will also be unable to field trialists Christian Ribeiro and Graham Cummins as the pair cannot sign deals with the club until the transfer embargo is lifted while former captain Danny Coles left for Forest Green this week.
Portsmouth manager Andy Awford could hand a debut to new arrival Paul Robinson when they visit St James Park.
A recent loan acquisition from Millwall, Robinson comes into the reckoning for a place at centre-back but will face opposition from Jack Whatmough, Ben Chorley and Joe Devera.
Elsewhere, Walsall's top scorer last season, Craig Westcarr, is expected to spearhead the Pompey attack while James Dunne could face his old club.
Ricky Holmes and former Grecian Ryan Taylor will be hoping for involvement having both returned to training this week but Patrick Agyemang is expected to miss out because of a thigh injury.