Ulster pair Stuart McCloskey and Tom O'Toole are among 12 players released by Ireland so they can have playing time with their provincial sides.
Ireland are not back in Six Nations action until 27 March against Italy.
Also released are Bundee Aki, Ultan Dillane and Dave Heffernan (all Connacht) along with Leinster trio Ryan Baird, Ross Byrne and Jack Conan.
Munster quartet Craig Casey, Andrew Conway, Shane Daly and Chris Farrell complete the 12-strong list.
Ulster scrum-half John Cooney, who provided specialist cover for Ireland's defeat by France on Sunday along with Harry Byrne and Eric O'Sullivan, has also returned to the Kingspan Stadium.
Ulster are in Pro14 action on Friday night with an away game against Glasgow Warriors.
Leinster travel to face the Dragons, also on Friday, while a day later Connacht host Cardiff and Munster take on Edinburgh.
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