This includes a site pencilled in for the Grand Union office building, designed by Richard Rogers Partnership, and the Windings residential block. Both are part of the Paddington Basin regeneration.
Under the new plan, the health trusts behind the scheme would lease the buildings for 37 years.
A meeting is due to be held today to discuss the plan. It will be attended by Chelsfield, the Department of Health and the Paddington Health Campus team, which includes St Mary's NHS Trust, the Royal Brompton & Harefield NHS Trust and Imperial College.
Under the original plan, the core of the campus would be built on the St Mary's site, to the south of the Chelsfield-owned land.
We continue to evaluate all the options that are available
Paddington campus statement
Building understands the findings of a joint review by the Department of Health, the Treasury and National Audit Office review will be out next week.
It is believed this will back the original plan as long as it adheres to the £800m budget.
One source close to the team said he doubted that the new option had a realistic chance of success. The source said: "This option would have to be better in all respects. I am not sure whether this would receive Treasury approval."
A statement from the campus project team would not comment directly on the Chelsfield option. It said: "We continue to evaluate all the options available in terms of the configuration of the site and how services are provided during construction.