Plans to build a new hospital for planned surgery in Hertfordshire are being looked at, a campaign group says.
Herts Valleys Hospital said a facility on greenfield land was being considered after the NHS rejected expansion plans for St Albans and Hemel Hempstead hospitals.
Herts Valleys Clinical Commissioning Group (CCG) confirmed to the BBC the plans must be re-evaluated and that one alternative proposal was a new-build.
It will release more information later.
NHS Improvement has been considering West Hertfordshire Hospitals NHS Trust's expansion proposal since February 2017.
Both the trust and the CCG told the BBC it was rejected because the cost - between £300m and £700m - was too high.
The regulator has now told the trust to come up with alternative proposals.
Herts Valleys Hospital, which has been campaigning for a new acute hospital for West Hertfordshire, has cautiously welcomed the proposal which would see a facility built between St Albans and Hemel Hempstead for "planned care", with the existing Watford Accident and Emergency unit being refurbished, as under current plans.
It said while residents hoped to see a new full acute hospital built, the plans were seen as a "first sign of some fresh thinking".
Chairman Peter Ingram said the group was "delighted" that the local NHS had "put a greenfield option back on the table - if only for planned care".
He added: "This new thinking from the local NHS could solve half of the problem we have in West Herts by providing a realistic option for planned care that is accessible for residents of St Albans, Watford and Dacorum."
Conservative MP for Hemel Hempstead, Sir Mike Penning, said local NHS managers had always been told by NHS England not to put a project forward that did not include a new-build.
"Hopefully common sense will prevail... and they will realise that the greenfield option is the only option," he said.
The trust and the CCG told the BBC they would release a statement later this week.