Republic of Ireland striker Robbie Keane has been ruled out of Tuesday's decisive Euro 2012 qualifier against Armenia by injury.
The LA Galaxy striker sustained an abductor muscle injury in Friday's 2-0 win over Andorra so he is replaced by Simon Cox.
Cox is preferred to his West Brom club-mate Shane Long.
Stephen Kelly replaces suspended Stephen Ward in defence while Richard Dunne returns in place of Darren O'Dea.
Dunne, outstanding in the Republic's battling 0-0 draw against Russia in Moscow last month, was suspended for the Andorra clash.
The Republic need a point on Tuesday to guarantee a play-off spot.
Mathematically, the Irish could still win the group but it appears highly unlikely as they need Andorra to beat Russia on Tuesday evening.
Dubliner Keane is Ireland's record scorer with 51 goals and his absence is a blow for Giovanni Trapattoni.
However, Cox has also impressed for the Irish since making his debut against Northern Ireland in May and scored in the 2-0 friendly win over Italy in Liege a month later.
Keane has embarked upon a series of gruelling trans-Atlantic journeys to play for the Republic since heading to the United States, although he insisted earlier this week that he was feeling no ill effects.
Armenia have scored more goals than us and we must pay very, very much attentionRepublic of Ireland manager Giovanni Trapattoni
Trapattoni acknowledged on Monday afternoon that Keane had been ruled out of the game on Sunday morning.
"I was a liar. Robbie was out yesterday and was free to go home with his friends or go to the pub," said the Republic boss.
"I didn't want the opponents to know whether he would play or not."
Asked to explain his decision to pick Cox, Trapattoni said: "He is not Keane, but he is similar to Keane.
"Long has different qualities - he is fast and maybe he will be better when the opponents are a little bit tired."
The Armenians, who lost 1-0 at home to Ireland in the first round of qualifiers in September last year, have won each of their last three games, against Andorra, Slovakia and Macedonia, and scored 11 goals in the process.
But asked if he had been surprised by their late surge, Trapattoni said: "No. Maybe if you know the players who play for Armenia, it is not a surprise.
"Armenia is a very, very strong team. They have scored more goals than us and we must pay very, very much attention."
Armenia will be without injured defender Robert Arzumanyan, who strained a muscle in his right leg in Friday's 4-1 win over Macedonia but defender Hrayr Mkoyan will be back from suspension.
Key Armenian players include Shakhtar Donetsk midfielder Henrik Mkhitaryan and Yura Movsisyan, who set up three goals in Friday's win.
Republic of Ireland team: Given (capt), O'Shea, Dunne, St Ledger, S Kelly, McGeady, Whelan, Andrews, Duff, Doyle, Cox.
