Ireland coach Joe Schmidt admitted he had to make a "number of tight calls across almost every position" as he named three uncapped players in his 38-man squad for the opening two rounds of the Six Nations.
Connacht's good form domestically sees uncapped trio Jack Carty, Caolin Blade and Tom Farrell all called up as Ireland look to defend the Grand Slam, while Leinster's Johnny Sexton, the reigning World Rugby Player of the Year, is making "good progress" in his recovery from a knee injury ahead of the tournament -- he is also named in the squad despite not playing since Dec. 29.
Peter O'Mahony, Sean O'Brien, John Cooney,Robbie Henshaw and Iain Henderson are all also carrying injuries but are all called-up.
"It's been great to watch the provincial teams doing so well in recent weeks," Schmidt said. "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.
"Those selected in the back row could well be joined by Dan Leavy once he's fully fit. With a cohort of young players emerging, it will keep plenty of pressure on the performances of the experienced guys.
"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.
"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."
Ireland kick-off their Six Nations campaign in Dublin against England Feb. 2.
Full Ireland squad:
Backs: Will Addison, Bundee Aki, Caolin Blade, Joey Carbery, Jack Carty, Andrew Conway, John Cooney, Keith Earls, Chris Farrell, Tom Farrell, Robbie Henshaw, Rob Kearney, Jordan Larmour, Conor Murray, Garry Ringrose, Jonathan Sexton, Jacob Stockdale
Rory Best, Tadhg Beirne, Jack Conan, Sean Cronin, Ultan Dillane, Tadhg Furlong, Cian Healy, Iain Henderson, Dave Kilcoyne, Jack McGrath, Jordi Murphy. Sean O'Brien, Peter O'Mahony, Andrew Porter, Rhys Ruddock, James Ryan, John Ryan, Niall Scannell, CJ Stander, Devin Toner, Josh van der Flier