Ulster back Jacob Stockdale has been left out of Andy Farrell's Ireland squad for the Six Nations.
Stockdale is unavailable after he injured his knee in Ulster's Pro14 win over Munster on 2 January but Leinster prop Tadhg Furlong has been included after recovering from long-term injury.
Uncapped Munster scrum-half Craig Casey is named in the squad but Ulster's John Cooney misses out.
Ulster prop Tom O'Toole is the only other uncapped player in the squad.
Leinster fly-half Johnny Sexton will continue to captain Ireland, who begin their Six Nations campaign against Wales in Cardiff on 7 February.
Furlong has not played since Ireland's Six Nations defeat by England in February due to calf and back problems but is one of 17 Leinster players named in the squad, alongside returning flanker Rhys Ruddock.
Iain Henderson has been named despite sustaining a knee injury against Scotland in November while Sexton, James Lowe and Peter O'Mahony have been included despite carrying knocks.
There is no room in the 36-man squad for Leinster forward Ryan Baird or Munster back row Gavin Coombes. Cooney has been unable to force his way back into Farrell's plans despite impressing for Ulster in recent weeks.
Casey, 21, gives Farrell a fresh option at scrum-half alongside Conor Murray and Jamison Gibson-Park. Leinster's Ross Byrne and Ulster's Billy Burns get the nod ahead of Connacht fly-half Jack Carty to deputise for Sexton.
"Since the Autumn international window the club season has had a good few disruptions and the cancellation of the European fixtures means there have been less opportunities for players to show form or to return from injury and get some minutes under their belts," said Farrell.
"Tadhg (Furlong) hasn't played in quite a while but he is ready to join the group. Unfortunately Jacob (Stockdale) will not be available to us."
Ireland finished third in the staggered 2020 Six Nations with three victories in five matches. Farrell's side also finished third in the inaugural Autumn Nations Cup after beating Scotland in the play-off.
Forwards: Tadhg Beirne, Will Connors, Caelan Doris, Ultan Dillane, Tadhg Furlong, Cian Healy, Dave Heffernan, Iain Henderson, Rob Herring, Ronan Kelleher, Dave Kilcoyne, Peter O'Mahony, Tom O'Toole, Andrew Porter, Quinn Roux, Rhys Ruddock, James Ryan, CJ Stander, Josh van der Flier.
Backs: Bundee Aki, Billy Burns, Ross Byrne, Craig Casey, Andrew Conway, Shane Daly, Keith Earls, Chris Farrell, Jamison Gibson-Park, Robbie Henshaw, Hugo Keenan, Jordan Larmour, James Lowe, Stuart McCloskey, Conor Murray, Garry Ringrose, Jonathan Sexton (captain).