Ireland scrum-half Isaac Boss has been ruled out of Saturday's RBS 6 Nations match against Scotland.
Boss will miss the Murrayfield encounter, which will see Ireland clinch the Triple Crown if they win, after suffering a shoulder injury during Ulster's league defeat against Llanelli Scarlets.
He was ruled out after a scan in Belfast on Monday and his injury will be reassessed next week when the Irish will be hoping to be heading for Italy with the championship within their grasp.
Boss, a try-scoring substitute in Ireland's 43-13 RBS 6 Nations demolition of England nine days ago, was cover for Peter Stringer.
Ireland coach Eddie O'Sullivan had already added Wasps scrum-half Eoin Reddan to his training squad as a potential replacement for Boss.
O'Sullivan is due to announce the starting line-up tomorrow.
Reddan is among 10 players called up for training, joining Geordan Murphy, Tommy Bowe, Barry Murphy, Rob Kearney, Frankie Sheahan, Bryan Young, Stephen Ferris, Jamie Heaslip and Trevor Hogan.