Johnny Sexton and Robbie Henshaw are set to return to Ireland duty in Saturday's Autumn Nations Cup game against Scotland but Billy Burns and James Lowe have been ruled out.
Captain Sexton and centre Henshaw missed the games against England and Georgia because of injury but both returned to training on Monday.
Burns sustained a groin injury in Ireland's lacklustre win over Georgia.
Wing Lowe was ruled out of Sunday's game because of a similar injury.
Both will miss the battle for third place in Dublin against the Scots in the new tournament, although Sexton's expected availability at fly-half will compensate for the absence of Ulster number 10 Burns.
The 26-year-old impressed on his first Ireland start, scoring their opening try on Sunday before going off shortly after half-time.
Sexton, 35, sustained a hamstring strain in Ireland's opening Autumn Nations Cup win over Wales with centre Henshaw, 27, injuring an abductor muscle in the same game.
Flanker Will Connors will continue to be monitored after being forced off for a head injury assessment last weekend but wing Keith Earls (back), scrum-half Conor Murray (dead leg) and hooker Rob Herring (rib) should be available to coach Andy Farrell.
Prop Ed Byrne will remain out because of an ongoing calf issue, while the uncapped duo of Ulster prop Eric O'Sullivan and Leinster fly-half Harry Byrne will remain with the squad this week.
Sexton defends Ireland record under Farrell
Speaking in a news conference on Tuesday afternoon, Sexton dismissed suggestions that the team have gone backwards under coach Farrell, and accused the media of being overly critical.
Farrell's first year in the job, which has included two disappointing defeats by England and one against France, was on Monday assessed as "an average return" by Irish Rugby Football Union performance director David Nucifora.
However, the Ireland skipper is adamant progress is being made and offered to show video footage to support his argument.
"If you're talking about results - which is what Test match rugby is about - there have been plenty of Irish teams over the years that have lost in Twickenham and have lost in France," said Sexton.
"Were they games we could have won? Maybe not the first England game. The second one and the French one, we definitely feel like there were things we did that got away from us.
"England were in a World Cup final, they're probably one of the better teams in the world at the moment and we need to get up to that level.
"Have we gone backwards? Not when you compare it to 2019. If you go and compare it to 2018 then obviously. But we went backwards in 2019, the same team went backwards.
"I know you guys [the media] don't agree but we feel like we're progressing and we need to show it, and that's where the gap in opinion is really.
"We can show you some video clips, if you want, of us creating lots of opportunities that we are just not finishing. That's what we feel, you can disagree if you want, but that's where we are."
Georgia display 'not our standard' - Sexton
Since stepping up from assistant coach to succeed Joe Schmidt after last year's World Cup, Farrell has chopped and changed with his selection, picking 40 players across eight fixtures and handing out a string of debuts.
Ireland finished third in the Guinness Six Nations and also attracted criticism for their laboured display in Sunday's underwhelming 23-10 win over the Georgians.
Sexton watched that game from the Aviva Stadium stands and echoed Farrell's post-match comments that the second-half showing was unacceptable.
"It's not our standard and we're not getting away from that," Sexton said.
"We hope to right those wrongs over this week and the Six Nations is massive then. We need to try and put it all together on Saturday."