BOSTON — Gov. Charlie Baker’s administration unveiled a plan Tuesday for major changes at Bridgewater State Hospital, a facility that houses and treats mentally ill men either charged with or convicted of a crime.

Under the overhaul, inmates who are serving criminal sentences would be moved out of Bridgewater and into new patient units at Old Colony Correctional Center, a nearby prison.

The administration plans to hire a private vendor to provide “enhanced medical and mental health treatment,” for patients who will remain at Bridgewater, including people sent there for evaluation to determine if they are competent to stand trial, and others who have completed their sentences but remain in custody under a civil commitment order.

The medium-security prison about 30 miles south of Boston has come under increased scrutiny in recent years, prompting calls to transfer control of it from the state Department of Correction to the Department of Mental Health.

In 2009, Joshua Messier, an inmate who was diagnosed with schizophrenia, suffered heart failure when guards forcefully strapped him to a bed. Three corrections officers later faced criminal charges in connection with the incident.

The suicide last year of a man who had been kept in isolation at the facility prompted a scathing report from the Boston-based Disability Law Center and a call from the organization to be placed into receivership.

Baker’s plan would keep Bridgewater under the jurisdiction of the Correction Department, but calls for officers to provide security largely at the perimeter of the 22-acre complex and have only limited contact with patients.

The changes, the Republican governor said in a statement, “will quickly initiate much needed change to balance public safety and medical treatment to better serve the facility and the Commonwealth.”

Christine Griffin, executive director of the Disability Law Center, called the plan a positive step in the right direction, but continued to call for the state’s mental health agency to eventually assume jurisdiction over Bridgewater. Such a change would require a vote from the Legislature, while Baker’s plan can be accomplished administratively.

“I think the major problem is that it’s run like a prison,” Griffin said. “There is too much focus on punishing people and not enough focus on providing people with treatment.”

The Boston Globe first reported Tuesday on the planned overhaul.