Republic of Ireland manager Giovanni Trapattoni has revealed that it was a "very difficult" decision to axe Kevin Foley from his 23-man squad for Euro 2012.
The Wolverhampton Wanderers defender was dropped from the national squad due to a hamstring injury.
The decision was not welcomed by the Irishman, who has admitted that he feels "betrayed" by the snub.
"We based our decision on the fact of the centre-halves all have problems," said Trapattoni. "We are not sure if they will be 100%. McShane did a careful medical check and we decided to include him in the 23.
"The reason behind this is we need one more central defender and we know they are more subject to bookings. I spoke to Kevin and with regret, I communicated my decision to him. Obviously, he was clearly upset. Also me.
"But I have a responsibility to our team and the Irish nation. It's my duty to take this decision disregarding personal feeling. For me and for [assistant] Marco [Tardelli], it was very difficult, but we had to decide on one defender more."
Ireland's first group game is against Croatia on June 10.