Mondry wouldn't elaborate on the negotiations, saying she didn't want to raise the community's expectations before the proposed contract was signed.
Gene Campbell, general partner of Pinnacle Fitness, said he was excited about closing the deal on the Laurel Heights site.
"The area's demographics are fantastic as far as the supply and demand for a health club," he said. "We're looking at this as a great opportunity for both of us."
If the deal is signed and if the city doesn't require too many improvements to bring the facilities up to code, Campbell estimated that the health club could reopen as early as this fall.
Pinnacle Fitness already runs two health clubs in downtown San Francisco, Campbell said. His business also owns or partly owns health clubs in Oakland, Pleasant Hill and Danville.
The JCC's fitness center and pool shut down at the end of May due to the center's ongoing financial crisis. A group of center members called Friends of the JCC tried unsuccessfully last spring to raise enough money to keep the fitness areas at 3200 California St. open for another year.
The latest transaction is part of the JCC's continuing efforts to ease its debt, estimated at $1.6 million at its peak. To help improve its financial standing, the JCC also sold its 1.9-acre site at 655 Brotherhood Way to Brandeis Hillel Day School late last year.