Chris Brunt, Roy Carroll, Martin Paterson and Sammy Clingan have pulled out of the Northern Ireland squad to face Georgia.
Derby goalkeeper Carroll has been forced out after suffering a groin problem, while West Brom midfielder Brunt is missing with a hamstring strain.
Clingan is unavailable because he is on club duty with Nottingham Forest and Scunthorpe striker Martin Paterson is in hospital with gastroenteritis.
Northern Ireland boss Nigel Worthington is also sweating over the fitness of Gareth McAuley and Kyle Lafferty.
Burnley forward Lafferty picked up a thigh problem during the weekend defeat to Preston, while Leicester defender McAuley has been carrying a knock for a while.