Leinster's international pair Luke Fitzgerald and Eoin Reddan are both in contention to face Newport Gwent Dragons this weekend.
Fitzgerald had been in flying form and looked certain to start in the Six Nations before injuring his groin last month.
The 26-year-old is now back in training and could feature this weekend, although Dave Kearney and Andrew Trimble have both impressed in Ireland's opening two matches. Their form has kept Fergus McFadden on the bench, with Simon Zebo and Craig Gilroy not making the squad.
Scrum-half Eoin Reddan should also be involved this weekend for Leinster after recovering from a groin strain of his own.
"[Fitzgerald] trained today so we just have to see how he responds to that session," O'Connor told the Irish Times.
"All things being equal you would like him to be involved this weekend but it is just one of those things.
"I think it was in the Ospreys game in the Heineken Cup when he pulled up tight.
"I think it was the groin. After that he didn't do a lot of training with the Irish group and hadn't recovered subsequently to play against Zebre. He looked good today, trained well.
"Redser is about the same. He picked up a calf strain in that (Ospreys) game, had a bit of a re-strain with Ireland at Carton House. He has done all his recovery, ticked all the boxes and should be involved as well."