Ulster scrum-half John Cooney, Connacht prop Finlay Bealham and full-back Mike Haley of Munster have been cut from Ireland's World Cup squad.
They returned to their provinces as their Irish colleagues left for warm weather training in Portugal.
Cooney's omission will be a surprise to many, given his club form and place-kicking ability.
Meanwhile, Ireland have said fly-half Joey Carbery is expected to be out for four to six weeks with an ankle injury.
Munster player Carbery sustained the injury during last Saturday's 29-10 win over Italy.
If Carbery, understudy to first-choice Johnny Sexton, needs the full six weeks to recover, he would be ruled out of Ireland's first World Cup pool match against Scotland on 22 September.
Ireland's other Pool A matches are against hosts Japan, Russia and Samoa.
Hooker Rob Herring, who retired from the Italy game early due to a back spasm, has fully recovered, Irish management said on Wednesday.
Three recognised number nines remain in head coach Joe Schmidt's 40-strong squad - Conor Murray, Kieran Marmion and Luke McGrath - with the final 31-player panel to be announced by 8 September.
Ireland play England in their second warm-up game at Twickenham on 24 August before playing Wales away and home.