Highland Council last year refused Inverness Properties' plan to build 16 homes within half a mile of the historic battlefield at Viewhill Farm.
However, the developers appealed and a Scottish Government-appointed reporter considered the application again, leading to planning permission being granted with conditions.
David Sutherland, former executive chairman of Tulloch Homes, bought the land from the developers. He has farming interests in the area. He said that any houses he built at Viewhill would not be seen from the battlefield
But Mr Sutherland also publicly stated that he was willing to sell the land to the trust, so long as it could be leased back for agricultural purpose and so forego housing development.
A spokesman for the National Trust for Scotland said: "The negotiations between the trust and Mr Sutherland continue and have thus far been positive and constructive. It remains our hope that we can find a solution and possibly acquire the land in question for the trust in order to safeguard the battlefield."
Earlier this year NTS chairman Sir Kenneth Calman called for a dialogue with ministers to try to find a way how planning law could better protect important historical sites