Skipper Aaron Hughes, Kyle Lafferty and George McCartney have pulled out of the Northern Ireland squad to play Scotland in Wednesday's friendly in Glasgow.
Fulham defender Hughes has an ankle injury while Rangers striker Lafferty came off with a hamstring problem after scoring against Hearts on Saturday.
West Ham full-back McCartney is recovering from a bout of pneumonia.
Northern Ireland boss Nigel Worthington has not brought in players to fill the void left by the trio.
Hughes was injured in Fulham's 2-1 defeat by Hull City in Saturday's Premier League opener at the KC Stadium.
Worthington may use the absence of Hughes to have a first look at Manchester United's Jonny Evans in central defence after a series of games at full-back.
McCartney is set to return to West Ham training on Monday after missing pre-season and Saturday's 2-1 league win over Wigan.
Dean Shiels and Michael Duff are back in the Northern Ireland panel for the Hampden Park game.
Hibernian midfielder Shiels won the last of his four caps 18 months ago and it is his first call-up since Worthington took over as manager.
Burnley defender Duff is back after recovering from an ankle injury.
Northern Ireland squad:
Goalkeepers: M Taylor (Birmingham City), A Mannus (Linfield).
Defenders: C Baird (Fulham), S Craigan (Motherwell), G McAuley (Ipswich Town), J Evans (Manchester United), M Duff (Burnley).
Midfielders: S Davis (Fulham), K Gillespie (Sheffield United), M O'Connor (Crewe Alexandra), S Clingan (Norwich City), C Brunt (West Bromwich Albion), D Shiels (Hibernian).
Forwards: D Healy (Fulham), P Thompson (Stockport County), W Feeney (Cardiff City – on loan at Dundee United); M Paterson (Scunthorpe United).
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