The former Wales international missed Saturday's goalless draw against Brentford through illness, and faces a race against time to prove his fitness for the game at the Ricoh Arena.
Rob Purdie came in to cover for the former Cardiff man, and will keep his starting place if Parry continues his absence.
Manager Graham Turner has limited options at the moment, forced into naming three youth team players on the bench against the Bees, and is unlikely to make any unforced changes to his team.
Turner could opt to reinstate Mark Wright as the winger gets back to full fitness following a knee injury.
Midfielder Luke Summerfield (hernia) and striker Ryan Doble (hand) remain absent.