Ireland have added Munster back rower Tommy O'Donnell and Leinster back Ian Madigan to their squad ahead of Sunday's clash with Scotland at Murrayfield.
Following an MRI scan on Monday, it was confirmed to the Ireland medical team that Ulster back-row Chris Henry suffered a cartilage tear to his right knee while playing last Friday.
The injury will require surgery and will rule Henry out of playing for approximately four weeks.
O'Donnell has thus been called into the squad as cover for this week after making an appearance for the Ireland Wolfhounds at the end of January.
Connacht centre David McSharry is also unavailable this week as he is still suffering from a niggling groin injury and so versatile Madigan has been called into the Irish camp.
Centre Luke Marshall, back-rower James Coughlan and second-rows Lewis Stevenson and Devin Toner had already been added to the squad as extra cover on Sunday.
Ireland Squad (30): Rory Best, Darren Cave, Tom Court, Sean Cronin, James Coughlan, Keith Earls, Luke Fitzgerald, Declan Fitzpatrick, Craig Gilroy, Robbie Henshaw, Jamie Heaslip, Iain Henderson, Paddy Jackson, Rob Kearney, David Kilcoyne, Ian Madigan, Luke Marshall, Fergus McFadden, Conor Murray, Sean O'Brien, Donncha O'Callaghan, Tommy O'Donnell, Brian O'Driscoll, Ronan O'Gara, Peter O'Mahony, Eoin Reddan, Mike Ross, Donnacha Ryan, Lewis Stevenson, Devin Toner.