Paul O'Connell also returns to the second row alongside Ireland's most capped player Malcolm O'Kelly, while the seven other members of the pack for the Scottish game also featured in the two-match Test series against Argentina. Simon Best, Jerry Flannery and Bryan Young renew their front row partnership.
Commenting on his selection, O'Sullivan said: "This is more than a warm-up match for the World Cup, for some it's a one-off game before the squad is selected. Some may not have expected (Paul) O'Connell and (Brian) O'Driscoll to start but they need to get on the pitch.
"Brian has not played since March and Paul has played just twice since then so it's important to get them on. We'll bring some players off the bench and give them the chance to play.
"We're trying to get access to areas of the team that we need more information about. At the moment it's the back row that is causing the greatest headache."
IRELAND TEAM & REPLACEMENTS (v Scotland, Murrayfield, Saturday, August 11, kick-off 2.30pm):
Player / Club / Caps
15 - Geordan Murphy Leicester (48)
14 - Brian Carney Clonakilty/Munster (2)
13 - Brian Oâ00Driscoll Captain UCD/Leinster (74)
12 - Gavin Duffy Galwegians/Connacht (6)
11 - Tommy Bowe Belfast Harlequins/Ulster (9)
10 - Paddy Wallace Ballymena/Ulster (4)
9 - Isaac Boss Ballymena/Ulster (8)
1 - Bryan Young Ballymena/Ulster (7)
2 - Jerry Flannery Shannon/Munster (15)
3 - Simon Best Belfast Harlequins/Ulster (18)
4 - Malcolm Oâ00Kelly St.Maryâ00s College/Leinster (85)
5 - Paul Oâ00Connell Young Munster/Munster (43)
6 - Neil Best Belfast Harlequins/Ulster (12)
7 - Stephen Ferris Dungannon/Ulster (3)
8 - Jamie Heaslip Clontarf/Leinster (2)
16 - Rory Best Belfast Harlequins/Ulster (12)
17 - John Hayes Bruff/Munster (73)
18 - Alan Quinlan Shannon/Munster (24)
19 - Keith Gleeson St.Maryâ00s College/Leinster (26)
20 - Eoin Reddan Wasps (2)
21 - Ronan Oâ00Gara Cork Constitution/Munster (71)
22 - Shane Horgan Lansdowne/Leinster (55)