Rob Kearney and Eoin Reddan took no part in training as Ireland coach Joe Schmidt put his squad through their paces at Carton House this morning ahead of Saturday’s clash with Italy in the RBS 6 Nations.
Kearney was sidelined by a hamstring strain, while Leinster team-mate Reddan is struggling with a tight calf.
Schmidt received a welcome boost as Tommy O’Donnell played a full role in training. The Munster back-rower suffered a stinger during Munster’s 26-5 win over the Dragons at Thomond Park on Saturday.
Fit-again Jared Payne will be waiting in the wings to slot in at 15 if Kearney is not fit for the match, in a move that would allow Schmidt to pair Stuart McCloskey and Robbie Henshaw in the centres again.
Simon Zebo could also deputise at full-back should Schmidt opt to restore his first-choice centre pairing of Henshaw and Payne.
Ulster's New Zealand-born three-quarter Payne admitted he will be happy to feature at either 13 or 15, having recovered from the hamstring problem that kept him out of action at Twickenham.
"I've always played wherever," said Payne, who switches comfortably between full-back and outside centre at Ulster.
"I'd played a lot of 13 in New Zealand and there were a few injuries at Ulster when I arrived so I was happy to slot in at full-back.
"But playing well for UIster is different from turning it on for a Test match.
"I think Joe would be silly not to look at the centre combination of Stuart McCloskey and Robbie Henshaw again at some point.
"They were pretty impressive against England, so I'm sure there'll be another chance to see them at some stage.
"Italy are going to be tough, they have some very good outside backs.
"So from full-back, wing or 13 they are all going to be pretty dangerous.
"So you have to be on top of your game to handle that and they will really test you.
"They've got some dangerous runners out there.
"I don't know if this is a game where you can shine at 15: you'd have to be pretty tight on your field positioning and defensive work to keep them quiet."
Payne admitted whoever starts at outside centre will face a tough battle to contain Italy's Exeter Chiefs centre Michele Campagnaro.
"Whoever marshals Campagnaro will have their work cut out and it will be tough," said Payne.
"He's probably been the form outside centre throughout the Six Nations I think.
"He's very quick and quite surprisingly strong, so whoever's got the job of looking after him will have a tough day.
"That would be nice to do that, but if you're at the back you run around a bit too, so you just do whatever you do."
Speaking after the training session, Ireland scrum coach Greg Feek told RTÉ Sport: “Rob had a bit of a hamstring issue, so he sat out, and Eoin Reddan had a calf. Tommy was OK.
“They were probably the only issues from today. We’ll wait and see where those guys are at on Thursday.”
With Ireland yet to record a win after three outing in the Six Nations, Feek attempted to isolate just what has gone wrong this seasons.
The former All Black opined: “I think probably our accuracy on attack and defence.
“Maybe when we’ve had chances, maybe we haven’t won the ball in crucial times or we’ve given up the ball.
“The referees have had some influence in that as well.
“But I think if we had have got a few of those positions right or those crucial turnovers right, I think that would have got us a win.”
Ireland’s scrum and lineout are likely to be targeted by Italy, with Schmidt’s men particularly struggling in the latter area in their loss to England.
“I think any team will try to have a crack at a set-piece,” Feek said.
“We know that we have to get it right. And we’re under no allusion, whenever we’ve played Italy they’ve tried to give us a go.
“Its about us getting our processes right in the scrum and the lineout.”
The team to play the Azzurri at Aviva Stadium will be named at lunchtime on Thursday.