Norwich's medical team withdrew Pilkington from Giovanni Trapattoni's squad to allow him sufficient time to recover from a knee injury.
The 24-year-old had been picked in the squad to face England at Wembley on May 29, Georgia in a friendly on June 2, the World Cup qualifier with the Faroe Islands on June 7, and the trip to face Spain in New York on June 11.
Pilkington said: "The (Norwich) management and the physio have pulled me out.
"I have been struggling with my knee so I need to get treatment through the summer and an extra four games is not going to help me through pre-season.
"I need a rest and I need the treatment that I am going to be getting through the summer in the off season, so hopefully I can put that behind me and come back pre-season 100% fit.
"It is unfortunate these injuries have popped up at the worst times for me, but like I say, I have got to put that behind me now, get right for next season and then hopefully see if I can get back in the (Ireland) squad.
"It wouldn't be right for me to go away and then come back in pre-season struggling."