Poznan: Republic of Ireland should have two stalwarts back in the line-up for their first match at Euro 2012 in goalkeeper Shay Given and defender John O`Shea.
Given had been struggling with back and calf issues, but has returned to full training and is set to add to his 122 caps on Sunday, while O`Shea proved his fitness in the recent 0-0 friendly draw with Hungary by playing the full 90 minutes.
Danien Duff and Aiden McGeady will look to add width to Ireland`s attack from the wings, but youngster James McClean will also be hoping for some minutes after an impressive campaign with Sunderland.
However, coach Giovanni Trapattoni must decide whether to go with five midfielders or add a partner for veteran striker Robbie Keane up front.
Meanwhile, Croatia boss Slaven Bilic will have to do without the services of Bayern Munich striker Ivica Olic, who will miss the duration of the tournament with a thigh injury. His place in attack should be taken by the in-form Nikica Jelavic.
Additionally, Olympique Lyonnais centre-back Dejan Lovren and Hamburg midfielder Ivi Illicevic have also been ruled out of the finals due to injury problems.
Nonetheless, there was some good news for Bilic as defender Vedran Corluka passed a late fitness test and is expected to be in the starting XI, so captain Dario Srna should feature in midfield rather than at right-back.