Jamie Heaslip will miss the Six Nations clash with England on March 1st after fracturing vertebrae in the win over France on Saturday.
A scan on the Ireland number eight's back has "revealed fractures of the transverse process of three vertebrae", according to the IRFU.
“Although this injury causes a good deal of discomfort, it does not impact on the structural integrity of the spine, and once healed should pose no long term issues,” the statement added. “Typically this injury is treated akin to a soft tissue injury; according to symptoms.
“Jamie is already feeling more comfortable and it is hoped that he will be available to play again in approximately four weeks.”
Ireland face Wales at the Millennium Stadium on March 14th, 26 days from today.
France lock Pascal Pape has been cited for the knee to Heaslip's back that seemingly caused the injury during the 18-11 win at the Aviva.
The former French captain received a yellow card from referee Wayne Barnes after the official had consulted with the television match official and watched replays of the incident on the big screen.
Barnes adjudged Pape’s action to be intentional, using the word ‘deliberate’ when brandishing the card.
James Cronin, meanwhile, had a minor knee procedure last week after an injury sustained in the opening Six Nations win over Italy. "He is recovering well and will be rehabilitated in Munster, " said the IRFU.