Giovanni Trapattoni has revealed Paul McShane was handed Kevin Foley's ticket to Euro 2012 amid fears of a crisis in central defence.
Wolves full-back Foley was devastated to be told on Tuesday that he would not be going to the finals despite being named in the initial 23-man party on May 7. McShane was only drafted in as the 24th member of the squad last week after being called up from stand-by with Richard Dunne, John O'Shea and Sean St Ledger all struggling with injury.
Although Dunne and St Ledger have since returned to action, Darren O'Dea has joined O'Shea on the sidelines in recent days, and Trapattoni said: "We based our decision on the fact of the centre-halves - Dunne, O'Shea and O'Dea - all have problems. We are not sure if they will be 100%."
The 73-year-old said he opted for McShane because he can play at both full-back and in the middle, and added: "The reason behind this is we need one more central defender and we know they are more subject to bookings."
Trapattoni, who took a similar decision to leave Roberto Baggio at home for the 2002 World Cup when he was Italy's manager, was clearly emotional as he outlined the reasons for his decision in Pistoia on Tuesday night.
He said: "I spoke to Kevin this morning 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.
"I said to him [Foley], 'We are happy if you decide to stay with us.' He said, 'Okay, I will think about it.' Obviously he is a little bit sad. That's normal."
Trapattoni's comments came after he had watched his team defeat a Tuscan Select XI 5-0 at the Stadio Melani, the home of Serie D club Pistoiese.
Robbie Keane's first-half double either side of Simon Cox's strike gave Ireland a commanding lead before he, keeper Keiren Westwood, Dunne and James McClean were given a breather.
Substitutes Shane Long and Jon Walters continued the good work after the break, the latter converting from close-range after Foley's free-kick had been parried.