A proposal to create a new hospital in Prince George’s County in partnership with the University of Maryland Medical System is inching closer to reality, according to several sources who have been briefed on the plans.

The proposed new facility, estimated to cost up to $500 million, would replace the struggling Prince George’s Hospital Center, according to the sources, who spoke on the condition of anonymity because no agreement has been reached.

It is unclear at this stage of negotiations whether the new medical center would be housed in the old hospital building, in a new building on the same grounds in Cheverly or in a new building elsewhere in the central part of the the county.

The goal is to create a state-of-the art hospital facility that would be the linchpin of a regional medical network serving Prince George’s as well as neighboring Calvert and Charles counties, some sources said.

But the price tag of the entire network could reach $600 million, according to sources. Much of the cost would be shouldered by the state and Prince George’s County. None of the sources provided details about how the project would be financed.

In a statement, university medical officials cautioned that there is no deal yet, and that the university system still “has not committed to move beyond a consultative role at this time. For further involvement, feasibility studies as well as state and local funding resources would need to be identified for any proposal to come to fruition.”

But if a deal is worked out, it would mark the end of a long political saga about the fate of Prince George’s Hospital Center, which was founded in 1944. With many uninsured patients, the 265-bed hospital in Cheverly has long been dependent on millions in public subsidies. Even with public money, its long- term survival has seemed far from assured.

The University of Maryland Medical System, the county’s proposed partner, is a health care power in the state. A private nonprofit, it has $2.5 billion in annual revenues, about 15,000 employees and more than 115,000 annual patient admissions, the most in the state.

Led by a board whose members are appointed by the governor, the university system has ties to 12 academic, community and specialty hospitals and could help bring top medical experts to Prince George’s.

The proposal under discussion also signals that big changes are likely for Dimensions Healthcare, the firm that operates Prince George’s Hospital Center and is receiving $30 million in annual county and state subsidies. Dimensions President Kenneth Glover did not respond to requests for comment.

According to some sources, the new hospital is expected to be in the central part of the county, as Prince George’s Hospital Center is. Renovating the hospital center or using some of the adjacent county-owned land in Cheverly to build a new hospital would be among the less expensive options. Alternatively, the county could look to other sites such as the vacant Landover Mall site and New Carrollton, where a new, mixed-use development is planned next to the Metro,

County Executive Rushern L. Baker III (D) and Lt. Gov. Anthony Brown (D), who have been leading efforts to improve Prince George’s ailing health care system, are scheduled to meet with university medical officials this week, Brown said.

“Don’t get fixated on the costs,” Brown said in brief interview, declining to discuss the proposal in detail.

Baker, who was traveling to a county officials’ meeting in Portland, Ore., was not available for comment. His office issued a statement saying that joint efforts among public officials and medical experts had led to a “potential solution,” that was still being worked out.

A breakthrough on the hospitalcould be a political boost for both Baker and Brown. Baker, elected in November, would be able to deliver on a campaign promise to find a long-term solution to the county-owned hospital’s problems. Brown, who is considering a run for governor in 2014, would be able to point to a major accomplishment in his vote-rich home county.

“We are seeking a long-term plan, hopefully connecting with an academic institution,” said Del. Tawanna P. Gaines (D-Prince George’s), who sits on the Dimensions board, along with several other elected officials.

Prince George’s County Council Chairman Ingrid M. Turner (D-Bowie), also a Dimensions board member, said that everyone is hoping a deal comes together. “We don’t have any final word,” she said.

While Prince George’s officials have suggested for several years that the university medical system should come to the county, university medical officials have privately expressed reservations about the reliability of the county’s political and financial support for such a deal.

In 2007, a $329 million, eight-year agreement to share with the state operating costs and hospital renovations in Prince George’s fell apart in the 11th hour. Jack B. Johnson (D), who was the county executive, backed it, but Camille Exum (D), the County Council chairman, caught many elected officials by surprise when she told the General Assembly that the council did not think the county could afford it.

Baker was among those who have long decried the situation. After taking office as county executive in December, he assigned a top aide, Brad Seamon, to look for solutions.

Del. Barbara Frush (D-Prince George’s), also a member of the Dimensions board, said she was optimistic about an agreement. Frush, who had worked on the 2007 deal that fell apart, recalled that she “sat down and cried” when it disintegrated.

“I would be thrilled if something is worked out,” she said.