Boston is preparing to put five city-owned parcels on the block, opening up key land that would help unlock one of the few remaining development options near downtown, Widett Circle.

The land, which currently houses the city’s tow lot and several other municipal functions, sits right next to Widett Circle, which has long been sought after by developers. Widett Circle, which owners New Boston Food Market have put up for sale, sits between the city-owned land, Interstate 93 and a rail yard, making the Frontage Road parcels crucial in any development.

“That stuff would be vital, because it would be access,” said Greg Vasil, chief executive of the Greater Boston Real Estate Board. “Would you want a tow lot on a project that you’re developing for millions of dollars?”

The New Boston Food Market put Widett Circle up for sale last year, but have not publicly identified a winning bid. The owners are reportedly close to finalizing the process. A representative of the company involved in the sale did not respond to multiple requests for comment.

Widett Circle has long been the subject of rumours, speculation and proposals, including playing a key role in the bid to host the 2024 Olympics, and is frequently mentioned as a possible home for a soccer stadium. Still, it is entirely possible the eventual owners could choose a standard development, perhaps leaning on lab space for biotech companies, like a project slated to be built at the site of the former Boston Flower Exchange.

“Developers view that as one of the last frontiers of developable land in the city,” Vasil said. “I’ve got to think it’s a lot of bigger developers in the city looking for the next big thing to do.”

At a hearing at City Hall yesterday, city officials asked the council to declare nearly 18 acres on Frontage Road between South Boston and the South End as surplus, and allow the land to eventually be transferred to the Boston Planning & Development Agency. The BPDA plans to issue a Request for Proposals seeking ideas for the land early next year.

City officials have hired Utile to study possible options for the land, including where else in the city the tow lot, public works, Boston police maintenance facility and other facilities could go. The RFP explicitly asks Utile to explore the development potential of the site.

Citing old buildings, rising tides and outdated spaces, Boston’s Chief of Streets Chris Osgood told the Herald there needs to be some urgency and that the city can’t “do nothing.”

“We’ve really identified two things. One, we have a need to be really investing in our basic city services hub,” Osgood said. “The heart of that is at Frontage Road right now. It’s a site where some of the buildings are ending their useful life and it’s a location that’s currently in a flood plain.”

Councilor Michelle Wu, chairwoman of the committee on planning, development and transportation, questioned whether the land should be sold off on its own without consideration of surrounding development, including Widett Circle.

“I think there should be a question of ‘Do we pursue another RFP that will be driven by developers or do we plan first, decide what will go there to a degree of specificity in terms of affordability, in terms of open space, in terms of transportation requirements, public access and then put that out there through the RFP to see who will find that opportunity attractive to implement?’ ” Wu said. “Overall, we should have a big picture plan that includes all of it.”

Wu said it is still unclear how the process of moving the tow lot would work, and whether it would be beneficial.

“There’s two pieces. There’s the city services side and then what happens from a development perspective,” she said. “We need a more carefully thought-out and planned process.”