Quinn Roux has been ruled out of the remainder of the Six Nations and is not expected back in action until at least May.
The 30-year old is to undergo surgery this week on a shoulder injury which he picked up just prior to the start of the Six Nations against Wales.
The South African had been included in Andy Farrell's original Six Nations squad but returned to Connacht for medical assessment after suffering the injury in the lead-up to the Welsh game.
Connacht coach Andy Friend said it was a big disappointment for Quinn, and that he's a loss to the province and Ireland.
Meanwhile, Connacht centre Peter Robb is also to undergo surgery this week for an abdomen injury. It will not be known until after surgery how long the 26-year old will be sidelined.