The Republic of Ireland have received a boost with news that Croatia, their opponents in their opening group game, will be without the striker Ivica Olic, who was ruled out of Euro 2012 with a thigh injury.

Olic's place in the Croatia squad will be taken by Dnipro's Nikola Kalinic, while his absence means Everton's Nikica Jelavic is likely to start Sunday's fixture in Poznan .

Olic, who is set to join Wolfsburg from Bayern Munich this summer, suffered the injury in a friendly draw with Norway at the weekend. He was due to fly home from Croatia's training camp in Munich later on Monday.

While Olic's absence raises questions about Croatia's lineup things could not be more settled in the Republic camp with their manager Giovanni Trapattoni confirming that, barring any "strange circumstances" the starting lineup for Monday's friendly against Hungary in Budapest would be the one who face Croatia on Sunday.

"The team that starts this [Hungary] game will be the team that starts against Croatia, unless there are strange circumstances." Trapattoni said. "Why should I announce this team now? It is an easy answer. It is the team that allowed us to achieve qualification, they are in good form and we shouldn't change.

"We can play with our eyes closed. If we need to change, the other players can play the same way, but I couldn't change because all of these players are doing very well. John O'Shea will show me if he is fit. When there is an injury, after the game we can say it is OK or there is a concern. But John does not need to play the whole game, maybe just for 70 minutes. It is no problem, because I am thinking about the Croatia game."

The Republic went into the friendly in Budapest defending an impressive 13-match unbeaten run, and while an extension of that run would provide them with the perfect send-off to Poland, simply getting through the 90 minutes with all 23 squad members intact was equally important.

Acutely aware of the misfortune which has befallen the England defender Gary Cahill, captain Robbie Keane knows exactly what is at stake. "I know at the back of your mind, you try your best, but as soon as you are on the pitch, it's very difficult. If there is a tackle there to be won, it's just normal that you go in to try to win it.

"The last thing anybody wants, and certainly the players, is for anybody to get injured. To miss a major tournament like this after all the hard work we have done over the last few years would be terrible for any player. I feel for the players, people like Cahill in his first major tournament, who miss out with an injury.

"We are hoping that after the game, we will be speaking about everyone having got through OK with a good win under our belt and look forward to Sunday's game."

The Republic will leave Hungary on Tuesday morning for their Gdynia base near the Polish city of Gdansk.