O'Brien, 20, is currently on loan with League Two Swindon Town, where he has played 14 games as the Robins sustain their push for the play-offs.
He will return to Ireland U21s hoping to add to his two international caps in a U21 European Championships qualifier with Sweden.
The game takes place on March 29th at 17:00 BST and will be shown via Irish national broadcaster RTÉ.
U21s manager JIm Crawford also named a group of Under-20s to play a friendly this month, and those lads, whose ranks include Palace's Killian Phillips, could be called into the U21s.
The two join Scott Banks as Palace Academy players with international action coming up.
You can find out how they all fare with updates from cpfc.co.uk, the official app and across our social media channels.