The Boston Globe has taken a big early step away from Morrissey Boulevard as it continues to arrange its leave-taking of the property it moved to 56 years ago.

On Tuesday, the newspaper’s chief executive officer, Mike Sheehan, told staff members via email that the John Henry-owned media company is “in the process of completing a purchase-and-sale agreement with Winstanley Enterprises. Winstanley is a Concord, MA-based, family-owned firm experienced in mixed-use development,” wrote Sheehan, “and would make a terrific steward of this place we’ve called home since 1958.

“Though we’ve reached an agreement in principle with the Winstanleys,” he added, there are still details to be worked out and a period of due diligence, so this is far from a ‘done deal.’ ”

The question of where the company is going to settle next is still up in the air, according to Sheehan, who in the memo to the staff noted that “We’re also working with Colliers to evaluate proposals from potential new sites for our headquarters and production. We have many exciting options in a number of locations, so it’s anyone’s guess — mine included — where we ultimately move.

“We’re looking to move sometime in late 2016/early 2017, “ he wrote, “so it won’t be long before we have a much clearer picture of our future.

On Wednesday, the news of the Globe’s potential buyer was still being reviewed by civic leaders in Dorchester.

“We’re hoping that Winstanley Enterprises would reach out to the community, because we are neighbors,” said Eileen Boyle, president of the Columbia-Savin Hill Civic Association.

A community task force appointed by former Mayor Thomas Menino and supervised by the Boston Redevelopment Authority (BRA) established new zoning rules for the Globe site through a master plan for Columbia Point that was completed in June 2011.

The 16 acre site is located in a “Community Commerical Subdistrict,” a zoning category intended to “encourage the development of neighborhood businesses which provide essential goods and services as well as jobs and entrepreneurial opportunities for the Dorchester community.”

Allowed uses, the prospectus notes, can include office space, day care centers and restaurants as of right; other uses, like multi-family housing, hotels and bars would need approvals from the city. Two uses are strictly forbidden at 135 Morrissey Boulevard under the zoning code: dormitories and stadiums.

The plan also addressed height and density, suggesting that taller 11-to-13 story buildings could be situated nearer to the MBTA’s JFK-UMass station, with smaller, six-story structures closer to the present-day Globe site.