Ireland could bank on uncapped Rory Scannell as their third fly-half option for the opening two RBS 6 Nations encounters after overlooking Ian Madigan.
Head coach Joe Schmidt has included just Johnny Sexton and Paddy Jackson as recognised fly-halves in his 40-man Six Nations squad, with Leinster's Joey Carbery still recovering from ankle surgery.
Schmidt has resisted the temptation to draft in Bordeaux playmaker Madigan, with Irish Rugby Football Union (IRFU) bosses previously admitting any stars based overseas would face a tougher fight for Test selection.
The uncapped Scannell brothers have fought their way into Schmidt's squad thanks to fine form with Munster, with centre Rory a potential back-up option at fly-half.
"It has been good to watch the players over the past two months and great to see many of them doing so well," said Ireland boss Schmidt.
"As always there were some difficult decisions but we feel that the group is a good mix with a number of key players having good experience and a number of newer players having gained valuable experience and confidence during the summer tour to South Africa and the recent autumn series."
Hooker Niall Scannell will compete with Leinster's James Tracy to understudy captain Rory Best, as Sean Cronin will miss the tournament with hamstring trouble.
Munster wing Andrew Conway represents the third uncapped star in Schmidt's wider squad to prepare for the opening clashes in Scotland and Italy.
Linchpin fly-half Sexton is included as expected despite battling a calf complaint, with Rory Scannell offsetting the loss of Ulster centre Jared Payne to a long-term kidney problem.
British and Irish Lions playmaker Sexton hobbled out of Leinster's 24-24 draw at Castres on Friday night, but his withdrawal is hoped to have been little more than precautionary.
Former Leinster star Madigan could still be drafted into Ireland's squad at a later date, but IRFU bosses are determined not to select overseas-based players where possible.
Performance director David Nucifora has previously laid out the IRFU's position that Ireland stars plying their club trade abroad leave themselves at a "disadvantage" for Test squad selection.
Ireland start their Six Nations campaign by travelling to Murrayfield to face Scotland on Saturday, February 4, and hope by that time to have Sexton back to full fitness.
Stuart Olding misses out with injury in the centres, handing his Ulster colleague Stuart McCloskey a recall.