Ireland second row Paul O'Connell has been ruled out of the upcoming three-match Test series in New Zealand.
O'Connell had been undergoing rehabilitation on a knee injury in London with a view to following the Irish squad down under.
However, the Munster man has failed to progress to the level required to allow him to take an active part in the tour.
Connacht forward Mike McCarthy has already been added to the squad as further cover among the forwards.
The news will come as a further blow to coach Declan Kidney who is already without Tommy Bowe, Luke Fitzgerald, Isaac Boss, Tom Court and Stephen Ferris because of injury.
Doubts also remain over the fitness of prop Mike Ross, who is recovering from a hamstring complaint.
Ulster duo Paul Marshall and Chris Henry were among the players added to the squad after Tuesday night's warm-up game against the Barbarians at Kingsholm.
Uncapped Connacht props Brett Wilkinson and Ronan Loughney were also included amid doubts over Ross's fitness.
Ferris was ruled out of the tour on Saturday, with Kevin McLaughlin drafted into the squad.
Flanker Ferris sustained a calf injury during the Heineken Cup final defeat by Leinster earlier this month.
O'Connell sustained his injury in a Pro12 game against Ulster.
Kidney had already named uncapped trio Ulster prop Declan Fitzpatrick, Munster hooker Mike Sherry and winger Simon Zebo for the Test series.
Ireland will play world champions New Zealand in Auckland on 9 June, with Tests in Christchurch and Hamilton to follow on 16 and 23 June.
Forwards: Rory Best, Sean Cronin, Declan Fitzpatrick, Cian Healy, Jamie Heaslip, Kevin McLaughlin, Sean O'Brien, Donncha O'Callaghan, Peter O'Mahony, Mike Ross, Donnacha Ryan, Mike Sherry, Dan Tuohy, Chris Henry, Mike McCarthy, Ronan Loughney, Brett Wilkinson.
Backs: Darren Cave, Gordon D'Arcy, Keith Earls, Rob Kearney, Fergus McFadden, Conor Murray, Brian O'Driscoll, Ronan O'Gara, Eoin Reddan, Jonathan Sexton, Andrew Trimble, Simon Zebo, Paul Marshall.