Ireland skipper Robbie Keane is out of Tuesday night's Euro 2012 qualifier against Armenia and could be sidelined for four weeks.
The 31-year-old Los Angeles Galaxy striker will continue to undergo treatment for an adductor muscle injury in the hope that he will be fit should Ireland gain the point they need to secure a play-off berth next month.
Keane's place will be taken at the Aviva Stadium by West Brom frontman Simon Cox, who has been preferred to club-mate Shane Long and Stoke's Jonathan Walters, while goalkeeper Shay Given will wear the captain's armband.
Stephen Kelly will replace the suspended Stephen Ward at left-back, while Richard Dunne returns from his ban as Darren O'Dea makes way.
Boss Giovanni Trapattoni has urged his team to show maturity as they chase a play-off spot.
Trapattoni, who remembers only too well the late equaliser the Republic conceded to his native Italy when they were on the brink of a famous World Cup qualifier victory, said: "Our fans are very important, but we must not think about 'Go, go, go!' to score a goal.
"In the past we have tried to score a goal, not scored a goal and conceded on the counter-attack.
"This is a test of or maturity. With maturity, we will look to win, but we have to think always about not conceding a goal. When I came here, I saw a DVD of the Irish team which was leading and attacked with eight players.
"It was the same when I was at Benfica, the people shouting 'Go, go, go!' and there were 18 players in the final 30 metres of the pitch. That means 80 metres of the ground is free, and that is very, very dangerous.
"We must do what we want to do, that's maturity. For our team, for our players, this is a good test to show that with this maturity, we can achieve the result we want. All that matters is the result."