Town are waiting for Gareth McAuley and Veliche Shumulikoski to return from international duty before the squad for Saturday's home game against Blackpool is finalised.
McAuley netted his first international goal as Northern Ireland won 3-0 in San Marino, while Shumulikoski was one of a number of Macedonian players subbed at half-time during their 1-1 friendly with Moldova in Turkey.
Alex Bruce was away with the Irish squad ahead of their 2-1 victory over Georgia in Dublin, but was left out of the 18.
Assistant manager John Gorman says the squad won't be confirmed until the duo return on Friday: "Alex trained this morning and is fine and Moritz Volz is back with us now after injury.
"Shumi and Gareth are not back with us until Friday and we will see what they are like, but we are not aware of any injury problems with them."
Full-back Volz played the whole of the 9-2 reserves victory over Colchester earlier in the week, his first game since returning to action after his groin injury.
Iván Campo is still sidelined due to his calf strain, while David Norris and Alan Quinn both miss Saturday's game after reaching five bookings.