Croatia were dealt a major blow when striker Ivica Olic was ruled out of Euro 2012.
Scans have revealed the full extent of the departing Bayern Munich frontman's thigh injury and he is expected to be out of action for between four and six weeks.
His place in the Croatia squad, who provide the Republic of Ireland's first opponents in Group C, will be taken by Dnipro's Nikola Kalinic.
A statement on the Croatian Football Federation's official website, www.hns-cff.hr, said: "Unfortunately, Ivica Olic will not participate at the European Championships in Ukraine and Poland, and as his replacement, coach Slaven Bilic has called Nikola Kalinic."
Olic, who is to join Wolfsburg, suffered the injury in a friendly draw with Norway at the weekend.
The Croatians open their campaign against the Republic in Poznan on Sunday evening.
