Listed developer British Land is heavily tipped to be included, because it owns some land on the 50-acre site. Peter Holloway, principal regeneration manager at the South-west RDA, said the list would include "the major players".
The appointment process has been brought forward from March next year. Holloway said the RDA and council decided to do this so that the developer could help advise on the masterplan, being drawn up by public consultation adviser BDOR and urban designer Derek Lovejoy Partnership.
He said the RDA and council would remain the key players, even after the 15-year appointment was made in the new year. He said: "We will remain the guiding hand on the tiller."
The move is the second in recent weeks to add impetus to the mixed-use scheme. Last month, Chris Cavanagh joined Bath council from English Partnerships as major projects regeneration manager.
Cavanagh will help to compose the outline planning application, due to be submitted early next year.
