O'Connell is rated 50-50 for the opening match
The injury riddled Irish team suffered another blow when it was confirmed that loose forward Stephen Ferris has been ruled out of action for at least two weeks with an ankle injury.
Ferris will not take part in the Tests against South Africa and Fiji, although no decision has yet been made on his availability for the match against Argentina.
The 27-year-old Irish loose forward, Ferris, limped out of Ulster's 45-20 bonus-point Pro12 victory over Edinburgh at Ravenhill at the weekend.
Ferris badly twisted his right ankle and it has swollen up considerably, the Ulster medical team reported.
Sidelined with a back injury for almost a month, Ferris was afforded the chance to prove his fitness in front of the Ireland team management, but he twisted his right leg awkwardly when he was tackled after making a typically surging run.
He was helped from the field and the shattered look on his face said it all.
While the extent of the injury is not known at this stage, his absence would be another major concern for Ireland coach Declan Kidney, who has seen his squad ravaged by injury.
Rory Best and Brian O'Driscoll were the latest victims last week, while the likes of Ronan O'Gara, Paul O'Connell, Cian Healy and Keith Earls have all been carrying injuries at the training camp in Co Kildare.
O'Connell is rated 50-50 for the opening match against the Springboks this coming Saturday.
Fullback Rob Kearney also failed to make the initial squad as he required back surgery.