Bulls lose another star player to injury
Regular captain Burger Odendaal was also withdrawn due to a rib injury and was replaced by John Jackson, with Handre Pollard taking over the captaincy.
The squad included only two players that have not featured in the tournament this season, with Edgar Marutlulle and Matthys Basson added to the squad. Marutlulle has 31 caps to his name already though, while Basson could make a first appearance for the Bulls if he is named in the matchday squad.
The coach opted for an extra prop, hooker and scrumhalf.
"We are very aware of the importance of this trip," said Mitchell.
"We will be facing a team playing with massive confidence and having their best run in the competition, so it will be a massive task to beat them at home.
"That said, we have set ourselves some targets this year and winning in Buenos Aires will take us a step closer to achieving those. So, we know what is at stake."
Lock Lodewyk De Jager left the field with a pectoral injury in the win over the Sharks and his scans confirmed that he tore a muscle in his chest wall.
He will be on the sidelines for four months.
Prop Lizo Gqoboka injured his toe and scans have revealed that he has torn a tendon that requires surgery.
He is expected to be out for four to six months.
Backs: Warrick Gelant, Travis Ismaiel, Johnny Kotze, Divan Rossouw, Jesse Kriel, John Jackson, Handre Pollard (captain), Manie Libbok, Embrose Papier, Ivan van Zyl, André Warner.
Forwards: Thembelani Bholi, Nicholas De Jager, Roelof Smit, Marco van Staden, Jason Jenkins, Rudolph Snyman, Handre Stassen, Trevor Nyakane, Conraad van Vuuren, Matthys Basson, Nqobisizwe Mxoli, Frans van Wyk, Jaco Visagie, Edgar Marutlulle, Adriaan Strauss.
Patrick Lambie reveals extent of his injury: