The medical advice has been that he rest and he will not be involved for the remainder of the 2012 RBS 6 Nations..
The Ireland management have confirmed that O2 Ireland Wolfhounds and Munster forwards coach Anthony Foley has been appointed in Smal's place to assist preparations for the last three weeks of the Championship.
Ireland head coach Declan Kidney said: "Our hope is that Gert will make a quick recovery and that he will be back working with the squad as soon as possible.
"The medical advice given to us is that he needs rest and that he would not be with us for the rest of the Championship.
"We felt that Anthony (Foley), as Munster and Ireland Wolfhounds forwards coach, was the best person to help us out in Gert's absence and we are delighted that both Munster and Anthony have agreed to our request."
Foley will complete his duties with Munster for their RaboDirect Pro12 game against the Cardiff Blues this evening and then join up with the Ireland squad ahead of tomorrow's clash with Italy.