Joe Schmidt has unveiled a 38-man panel for Ireland's first two games in this year's Six Nations campaign.
Among them are three uncapped players - all from Connacht. Centre Tom Farrell, out-half Jack Carty and scrum-half Caolin Blade all get the nod.
Carty's inclusion comes at the expense of Ross Byrne.
There is no Dan Leavy, but Schmidt says the Leinster flanker will likely return when fully fit.
Munster lock Tadhg Beirne and Ulster back Will Addison have been named in a Six Nations squad for the first time as the countdown continues to next month's opening match against England at the Aviva Stadium.
Beirne made his international debut during the summer tour to Australia, Addison against Italy in November.
With Luke McGrath injured and Kieran Marmion also ruled out, the uncapped Connacht scrum-half Caolin Blade is also included.
Joe Schmidt said: "It’s a great opportunity for Caolin Blade to get into camp and compete for a spot."
He is one of three uncapped players in the squad, the other two being fellow Connacht players Jack Carty and Tom Farrell.
Schmidt said: "Conor Murray is back but Luke McGrath's knee injury against Toulouse is likely to rule him out of the Six Nations.
"Kieran Marmion is not too far away from returning but John Cooney will hopefully be back this weekend for Ulster. "
Schmidt said: "It's been great to watch the provincial teams doing so well in recent weeks. With another very competitive round of EPCR this weekend, the following Ireland squad for the first two matches of the Six Nations has been selected, knowing that late changes may be required, depending on how the matches go in the weekend. There have been a number of tight calls across almost every position."
Schmidt noted that there were a number of 'tight calls' across the positions
"In the front row, Finlay Bealham was very close, as was Marty Moore, who is getting back to the form that saw him win 10 caps in the past and Stephen Archer was at his combative best in Gloucester at the weekend.
Rob Herring is very unlucky as his performances for the National team have been first rate. Denis Buckley has done well for Connacht and the promising young loose heads Ed Byrne and Eric O'Sullivan have continued to impress.
Quinn Roux was very close to selection in the second row, which has become highly competitive with youngsters Gav Thornbury, Fineen Wycherley and Kieran Treadwell all impressing of late along with the experienced Billy Holland.
Even more competitive is the back row, where those selected could well be joined by Dan Leavy once he's fully fit. Sean Reidy continues to be all action for Ulster and Tommy O'Donnell is starting to get back to top form as well after his recent return from injury.
Here's the Ireland squad for the opening rounds of @SixNationsRugbyJanuary 16, 2019
With a cohort of young players emerging, it will continue to keep plenty of pressure on the performances of the experienced back rowers who have been selected."
Schmidt went on to explain his tight calls within the backs.
He said: "Johnny Sexton is making good progress, while Joey Carbery and Jack Carty have both performed consistently well so far this season. Ross Byrne is unlucky in an incredibly tight call. He is still definitely in our thinking and will continue to press for inclusion through the Six Nations and beyond, while Billy Burns has also fitted in really well for Ulster this season.
"Bundee Aki and a fresh and fully fit Robbie Henshaw squeeze out Rory Scannell, who was great for Munster last Friday, and Stu McCloskey, who continues to give Ulster gain line as well as defensive solidity.
"At outside centre Tom Farrell has forced his way into contention and Chris Farrell is working his way back to match fitness, improving week by week. We're sure that Sam Arnold and Rory O'Loughlin will continue to improve and both have plenty of promise.
Adam Byrne and Dave Kearney were both very good against Toulouse. The Connacht outside backs have been consistently good; Mike Haley is growing into his role with Munster while we look forward to a fit again Darren Sweetnam gaining some game minutes over the coming weeks."
Ireland Squad (Guinness Six Nations 2019 - Rounds 1 & 2)
Rory Best (Ulster/Banbridge) - Captain
Tadhg Beirne (Munster/Lansdowne)
Jack Conan (Leinster/Old Belvedere)
Sean Cronin (Leinster/St Mary's College)
Ultan Dillane (Connacht/Corinthians)
Tadhg Furlong (Leinster/Clontarf)
Cian Healy (Leinster/Clontarf)
Iain Henderson (Ulster/Queens University)
Dave Kilcoyne (Munster/UL Bohemians)
Jack McGrath (Leinster/St Marys College)
Jordi Murphy (Ulster/Lansdowne)
Sean O'Brien (Leinster/UCD)
Peter O'Mahony (Munster/Cork Constitution)
Andrew Porter (Leinster/UCD)
Rhys Ruddock (Leinster/St Mary's College)
James Ryan (Leinster/UCD)
John Ryan (Munster/Cork Constitution)
Niall Scannell (Munster/Dolphin)
CJ Stander (Munster/Shannon)
Devin Toner (Leinster/Lansdowne)
Josh van der Flier (Leinster/UCD)
Will Addison (Ulster/Enniskillen)
Bundee Aki (Connacht/Galwegians)
Caolin Blade (Connacht/Galwegians)
Joey Carbery (Munster/Clontarf)
Jack Carty (Connacht/Buccaneers)
Andrew Conway (Munster/Garryowen)
John Cooney (Ulster/Terenure College)
Keith Earls (Munster/Young Munster)
Chris Farrell (Munster/Young Munster)
Tom Farrell (Connacht/TBC)
Robbie Henshaw (Leinster/Buccaneers)
Rob Kearney (Leinster/UCD)
Jordan Larmour (Leinster/St Mary's College)
Conor Murray (Munster/Garryowen)
Garry Ringrose (Leinster/UCD)
Jonathan Sexton (Leinster/St Marys College)
Jacob Stockdale (Ulster/Ballynahinch)