Simon is comfortable and all his symptoms have resolved and he has been joined by his wife Katie who arrived in Bordeaux this afternoon. He will remain in hospital for further tests and it is hoped that he will be able to return home to Ireland in the next 24 to 48 hours.
Ireland coach Eddie O'Sullivan said: "This is very positive news for Simon and we will all continue to monitor his progress carefully. The care he has received so far has been excellent and the team doctor, Dr. Gary O'Driscoll, has been with him throughout this."
In further team news, both Jerry Flannery and Rory Best came through fitness tests during this afternoon's training session at Stade Bordelais. Flannery has been named to start at hooker, with Rory Best being named amongst the replacements.
O'Sullivan continued: "We have named Rory Best on the bench for this weekend and while we did consider his brother Simon's condition when making that decision, Rory is an incredibly mentally tough individual and was adamant that he wanted to be considered for selection. We have no doubts that he will be ready if called upon."
IRELAND TEAM & REPLACEMENTS (v Argentina, Parc des Princes, Sunday, September 30, 4pm Irish time/5pm local time):
15 â00 Geordan Murphy (Leicester)
14 â00 Shane Horgan (Boyne/Leinster)
13 â00 Brian O'Driscoll (UCD/Leinster) (captain)
12 â00 Gordon D'Arcy (Lansdowne/Leinster)
11 â00 Denis Hickie (St. Mary's College/Leinster)
10 â00 Ronan O'Gara (Cork Constitution/Munster)
9 â00 Eoin Reddan (Wasps)
1 â00 Marcus Horan (Shannon/Munster)
2 â00 Jerry Flannery (Shannon/Munster)
3 â00 John Hayes (Bruff/Munster)
4 â00 Donncha O'Callaghan (Cork Constitution/Munster)
5 â00 Paul O'Connell (Young Munster/Munster)
6 â00 Simon Easterby (Llanelli)
7 â00 David Wallace (Garryowen/Munster)
8 â00 Denis Leamy (Cork Constitution/Munster)
16 â00 Rory Best (Belfast Harlequins/Ulster)
17 â00 Bryan Young (Ballymena/Ulster)
18 â00 Malcolm Oâ00Kelly (St. Mary's College/Leinster)
19 â00 Neil Best (Belfast Harlequins/Ulster)
20 â00 Isaac Boss (Ballymena/Ulster)
21 â00 Paddy Wallace (Ballymena/Ulster)
22 â00 Andrew Trimble (Ballymena/Ulster)
Not considered due to injury:
Girvan Dempsey (shoulder) (Terenure College/Leinster)