Ireland prop Cian Healy will miss his side's final two games of the Six Nations tournament against Italy and France following a hip injury.
The 32-year-old sustained the blow during the recently concluded game against England where he was forced off the field in the 26th minute and now will spend time on the sidelines.
The news also means Healy will continue to remain at 98 Test games for Ireland and was set to make his 100th Test milestone when Ireland meet France in Paris on 14th March.
Will Connors, Max Deegan, Chris Farrell, David Kearney, Luke McGrath and Jack O'Donoghue have been released from the squad for club duty while Billy Burns, Stuart McCloskey, Jack McGrath and Tom O'Toole will be part of the training camp as Ulster's game against Benetton following the postponement of the fixture.
The squad will assemble on Wednesday for a two-day training camp in Dublin.
Ireland are positioned third in the Six Nations table with two wins from three games.
Ireland's 28-man training squad:
Forwards: Ultan Dillane, Caelan Doris, Tadhg Furlong, Dave Heffernan, Iain Henderson, Rob Herring, Ronan Kelleher, Dave Kilcoyne, Jack McGrath, Peter O’Mahony, Tom O’Toole, Andrew Porter, James Ryan, CJ Stander, Devin Toner, Josh van der Flier
Backs: Bundee Aki, Billy Burns, Ross Byrne, Andrew Conway, John Cooney, Keith Earls, Robbie Henshaw, Jordan Larmour, Stuart McCloskey, Conor Murray, Jonathan Sexton, Jacob Stockdale