Ireland have called up Shane Jennings and Luke Fitzgerald for this Saturday's game with Australia after Chris Henry and Keith Earls were ruled out.
Ulster back-row Henry tore his hamstring against Samoa and will be out for between four and six weeks and utility back Earls remains out of action having missed last weekend's game because of a knee injury.
Wing Tommy Bowe is a doubt for the match having taken a kick to his calf in the 40-9 win in Dublin.
Fly-half Jonathan Sexton is however set to return to take on Australia having missed the Samoa match with a hip injury.
Team manager Mick Kearney said: "Unfortunately Chris suffered a hamstring tear on Saturday and will miss the rest of the series, so Shane Jennings has been called in as a replacement.
"Tommy Bowe took a kick to his leg early on, it's sore and bruised but he's unlikely to train today and tomorrow, so Luke Fitzgerald has been called in as a replacement for Tommy for today.
"Jonny Sexton is expected to train fully and be available for selection, and otherwise everyone came through well.
"Keith Earls has been slow to settle and won't be available this week and will continue to be monitored."