Shane Long is out of the first leg of the Republic of Ireland's Euro 2016 play-off against Bosnia-Herzegovina on Friday evening.
However, the 28-year-old Southampton striker has not been ruled out of the return in Dublin next Monday.
Manager Martin O'Neill was keeping his fingers crossed as he met the media on Wednesday afternoon that Long, who scored the only goal in last month's famous 1-0 qualifying victory over world champions Germany, would be fit for the game in Zenica after damaging his foot in Poland three days later.
However, despite making progress, the frontman will not be available for the game at the Bilino Polje Stadium.
A Football Association of Ireland statement said: "Shane Long will not be involved in Friday's first leg as he will remain at Southampton for further treatment on his ankle injury, but he has not been ruled out of next Monday's second leg at the Aviva Stadium."
There was better news for Brentford midfielder Alan Judge, who was due to meet up with the squad in Dublin on Wednesday evening after recovering from a hamstring problem, and he will be joined by Charlton keeper Stephen Henderson following Keiren Westwood's withdrawal.
The statement added: "Henderson has been drafted into the squad as a replacement for Keiren Westwood who has returned to Sheffield Wednesday after a pre-existing ankle injury flared up today in training at the FAI National Training Centre."
It has proved a difficult few days for Ireland's goalkeepers with Shay Given sidelined by knee surgery and Rob Elliot, who played in Newcastle's 1-0 win at Bournemouth on Saturday, having been ruled out of the first leg with an ongoing thigh problem.
O'Neill said: "Rob himself, while feeling that he is not great, would obviously want to do something, but he doesn't feel as if he's 100 per cent fit, or possibly not even 80 per cent fit, so from that viewpoint, even though he did splendidly in the game, I think we are served well enough."