Paul Smyth has joined Jonny Evans as an injury absentee for Northern Ireland's Euro 2024 Group H qualifier against Finland in Helsinki on Friday.
Smyth will remain with his club Queens Park Rangers to have treatment on a hamstring injury, but may be available for Monday's game with Denmark.
Rangers winger Ross McCausland has been called into Michael O'Neill's squad.
Goalkeeper Bailey Peacock-Farrell is a major doubt, with Paddy Lane among the other players carrying knocks.
The Portsmouth winger has a calf complaint and is regarded as a doubt for the forthcoming double-header, which will conclude the European Championship qualifying campaign.
Burnley stopper Peacock-Farrell did not play for Danish side Aarhus, with whom he is currently on loan, at the weekend.
Portsmouth's Terry Devlin and West Ham teenager Michael Forbes have been added to the squad for training purposes ahead of the trip to Finland and next week's encounter with the Danes at Windsor Park.
Manchester United defender Evans is missing with a thigh strain after being forced off after 13 minutes of their recent Champions League defeat in Copenhagen.
Northern Ireland have lost six of the eight qualifying games they have played to date, their sole wins coming in home and away fixtures against group minnows San Marino.
Smyth scored a goal in a 3-0 victory over San Marino in Belfast in October on his first senior international start.
He then turned provider to set up Josh Magennis for Northern Ireland's second goal and had another fine finish disallowed for offside in a busy first half for the Queens Park Rangers man.
McCausland impressed as a substitute in Rangers' 2-1 Europa League triumph over Sparta Prague last week and was then named in manager Philippe Clement's starting XI for Sunday's Scottish Premiership win over Ross County, his first start for the Glasgow giants.