The Norwich City and Spartak Moscow players have been ruled out of Wednesday's friendly international through injury
Norwich City attacking midfielder Pilkington had been expected to make his Irish debut in midweek, but was forced off injured after just 24 minutes of the Canaries' Premier League tie with QPR.
Scans confirmed that the 24-year-old picked up a hamstring strain, with Pilkington taking to Twitter to express his disappointment.
"Gutted I can't meet up with the @FAIreland squad tomorrow because of my Hamstring strain! Hopefully get back fit and get in the next squad," Pilkington tweeted.
Aiden McGeady watched from the sidelines on Thursday as Spartak Moscow beat Bunyodkor Tashkent 2-1 in a mid-season friendly due to an ankle injury.
An FAI press release stated that the winger will "remain at his club for further treatment", while also adding that "an update will be issued later today should the manager decide to call in any replacements".