Calvary Baptist Church at 123 W. 57th St. in Manhattan. Keith Bedford for The Wall Street Journal

The developer of the One57 condominium project that soars 90 stories above Central Park is negotiating to purchase another development parcel just a couple of lots away—at the current site of Calvary Baptist Church.

Gary Barnett ’s Extell Development Co. is in talks with Calvary Baptist, which owns its church building and the Salisbury Hotel, both at 123 W. 57th St., according to documents posted on the church website and available in its lobby.

A report in September from the church board to its membership says the church has signed a letter of intent with Extell that allows the board to begin negotiations with the company regarding potential redevelopment of the church’s property.

Public records show the church and hotel together occupy about 191,000 square feet.

The church’s documents say that FXFOWLE Architects and Extell’s architectural team are working together to present a design concept. The church also said in documents that it had hired London-based Savills PLC—which recently acquired New York’s Studley Inc.—as its broker, and Fried, Frank, Harris, Shriver & Jacobson LLP as its attorneys.

Extell representatives declined to comment. A representative for the church didn’t respond to requests for comment. Members of the firms that the church has hired either didn’t respond or declined requests for comment.

Extell also owns a 15-story apartment building directly backing onto the church and hotel site at 134 W. 58th St.

Many city churches are struggling with mounting maintenance costs as their buildings age. Many also sit on some of the city’s most valuable land. A growing number have been selling their land to developers and either moving to new locations or striking deals with developers to allow them to build over the top of church facilities.

One57 is seen in Manhattan in July. Keith Bedford for The Wall Street Journal

A May 1882 article in the New York Times said Calvary Baptist Church purchased its land for $160,000 and expected the cost of construction to be $200,000. In 2009, the church sold more than 30,000 square feet of air rights for $28.6 million to Extell for its development of One57.

While Mr. Barnett’s plans are unclear, if he buys the church and hotel and moves forward with a new project, it could reignite controversy about development on the street, including the shadows some of it throws on Central Park.

“We are extremely concerned about development along 57th Street,” said Layla Law-Gisiko, chairwoman of Community Board 5’s landmarks committee.

Write to Laura Kusisto at laura.kusisto@wsj.com