Harlequins prop Mike Ross will make his senior Ireland debut in the non-capped match in the front row with Rory Best and Bryan Young.
The back row sees Jamie Heaslip, who was first choice number 8 throughout this year's Six Nations tournament, joined by his Leinster colleague Shane Jennings and Ulster's Stephen Ferris in a new combination.
In the back-line, captain Brian O'Driscoll and Luke Fitzgerald will form a new centre partnership. Isaac Boss and Paddy Wallace are the half-backs and the back-three contains Shane Horgan and Tommy Bowe on the wings with Rob Kearney at full-back.
In the replacements, there are four uncapped players in Tom Court, Ryan Caldwell, Jonathon Sexton and Frank Murphy.
Commenting on the game, Michael Bradley said: "These games are always exciting, high tempo matches. From that perspective it will be good preparation for us as we head into the tour where the teams have been playing a fast and loose game under the new ELVs.
"The Baa Baas game will be important for the players to get up to that pace of play before we arrive in New Zealand and also for the Churchill Cup players in the match squad ahead of that tournament.
"Overall, the array of talent that the Baa Baas will have on show is of the highest calibre, so it will be good test for us, but I think we can get an awful lot out of the game ahead of the tour.
Commenting on the new centre partnership, Bradley added: "I suppose one of the main talking points of the selection will be the new centre partnership as there has been plenty of discussion about where Luke's best position is.
"This was the ideal opportunity to try Luke in midfield in a pressure situation against quality opposition and both he and Brian (O'Driscoll) have enough talent to make it work."
IRELAND TEAM & REPLACEMENTS (v Barbaians, Kingsholm, Gloucester, Tuesday May 27, kick-off 7.45pm):
15 - Rob Kearney (UCD/Leinster)
14 - Shane Horgan (Boyne/Leinster)
13 - Brian O'Driscoll (UCD/Leinster) (capt)
12 - Luke Fitzgerald (Blackrock College/Leinster)
11 - Tommy Bowe (Belfast Harlequins/Ulster)
10 - Paddy Wallace (Ballymena/Ulster)
9 - Isaac Boss (Ballymena/Ulster)
1 - Bryan Young (Ballymena/Ulster)
2 - Rory Best (Belfast Harlequins/Ulster)
3 - Mike Ross (Harlequins)
4 - Bob Casey (London Irish)
5 - Malcolm O'Kelly (St. Mary's College/Leinster)
6 - Stephen Ferris (Dungannon/Ulster)
7 - Shane Jennings (St. Mary's College/Leinster)
8 - Jamie Heaslip (Clontarf/Leinster)
16 - Bernard Jackman (Clontarf/Leinster)
17 - Tom Court (Ballymena/Ulster)
18 - Ryan Caldwell (Dungannon/Ulster)
19 - Neil Best (Belfast Harlequins/Ulster)
20 - Frank Murphy (Leicester)
21 - Jonathan Sexton (St. Mary's College/Leinster)
22 - Girvan Dempsey (Terenure College/Leinster)