Andrew Trimble and Roger Wilson were among four players called into the Ireland training squad on Monday ahead of next month’s Guinness Test series.
Many had felt winger Trimble should have been among the initial 34-man panel selected.
The Ulster duo were called up to the panel on Monday along with Munster lock Donncha O’Callaghan and Leinster prop Martin Moore.
The quartet come in because of injury doubts over four players.
Paul O’Connell, Keith Earls, Declan Fitzpatrick and Cian Healy sat out training at Carton House yesterday.
Munster lock O’Connell has a calf strain, while team-mate Earls will miss the rest of training this week because of a knee problem.
Ulster’s Fitzpatrick is struggling with a calf problem and fellow prop Healy is sidelined with a knee cartilage injury.
Munster scrum-half Conor Murray is also a doubt after being cited for striking with the elbow during Friday’s RaboDirect PRO12 win over Glasgow.
If found guilty at tomorrow’s hearing, Murray could be banned for eight weeks.
However, Ireland are hopeful, having reviewed the footage, that it will fall on the lower end of the scale and he would perhaps get a two week ban which would still leave him available to face Samoa in the opening game in the Aviva on November 9.
Sean O’Brien (knee) and Robbie Henshaw (hip) also missed the opening training, but on the plus side Brian O’Driscoll took part in the session following a calf injury and was expected to train the remainder of this week.
There was also better news for Ulster hooker, Rory Best, after he turned his ankle in the PRO12 victory over Cardiff Blues last Friday night.
He was expected to train today and as expected to make a full recovery.
It is an extensive list and not ideal for new coach Schmidt as he prepares for his first big tests with Australia and New Zealand following after the Samoa game on November 16 and 24 respectively.
Ireland manager, Michael Kearney said: “It’s obviously not ideal. We have brought in the four players as extra cover.
“We’ll train this afternoon, the forwards did some line-outs this morning while the backs did some skills.
“They’ll train for an hour this afternoon. We then have an open session for an hour from 11.30 tomorrow in the Aviva. Back in Wednesday evening and train Thursday and Friday.
“Most of the guys then will have the weekend off and some will be released back to their clubs to play in the Rabo.”
While some players are expected to be released back to their clubs, the Irish management were hoping some would remain ‘rested’.