Veteran Test flanker Rocky Elsom will also return to the starting XV in place of Dave Dennis and Chris Alcock is back in the No 7 jersey in a squad named by coach Michael Foley on Wednesday.
Ashley-Cooper, who has played inside centre for the Wallabies, has been moved in from fullback to partner Rob Horne, who returns from a two-game suspension this week.
The change has been made to shore up the Waratahs' defence in the mid-field and give five-eighth Berrick Barnes some solid support, which he sorely missed against the Brumbies last weekend.
Daniel Halangahu will play fullback and Tom Kingston returns to the wing after two weeks at centre. He will partner Atieli Pakalani, who has been named on the left wing.
Barnes will partner with former Cheetahs halfback Sarel Pretorius, who makes a return to the starting side after several rounds on the bench supporting Brendan McKibbin.
Pretorius is an excellent attacking player and is also believed to be an asset against South African teams.
In the forwards, Elsom's long-awaited return comes just in time to help the Waratahs combat the Bulls' intimidating pack.
Dean Mumm will start at lock on Friday after being rested last week.
John Ulugia will be tested as hooker after Tatafu Polota-Nau failed to shake off concussion concerns in time to be named this week.
And the Waratahs will welcome the return of hard-working flank Alcock to the field after two weeks' recovery from appendicitis.
Teams:
Waratahs: 15 Daniel Halangahu, 14 Tom Kingston, 13 Rob Horne, 12 Adam Ashley-Cooper, 11 Atieli Pakalani, 10 Berrick Barnes, 9 Sarel Pretorius, 8 Wycliff Palu, 7 Chris Alcock, 6 Rocky Elsom (captain), 5 Kane Douglas, 4 Dean Mumm, 3 Sekope Kepu, 2 John Ulugia, 1 Benn Robinson
Substitutes: 16 John Mann-Rea, 17 Jeremy Tilse, 18 Sitaleki Timani, 19 Lopeti Timani, 20 Dave Dennis, 21 Brendan McKibbin, 22 Tom Carter
Bulls:
15 Zane Kirchner, 14 Akona Ndungane, 13 Johann Sadie,
12 Francois Venter, 11 Bjorn Basson, 10 Morné Steyn, 9 Francois
Hougaard, 8 Pierre Spies, 7 CJ Stander, 6 Deon Stegmann, 5 Juandré
Kruger, 4 Flip van der Merwe, 3 Werner Kruger, 2 Chiliboy Ralepelle, 1
Dawie Steyn
Substitutes: 16 Willie Wepener, 17 Rayno Gerber, 18
Wilhelm Steenkamp, 19 Arno Botha, 20 Jano Vermaak, 21 Louis Fouché, 22
JJ Engelbrecht