Four of Gov. Deval Patrick’s top Cabinet officials plan to resign rather than commit to serving out the remaining two years of his term in a dramatic shakeup of the governor’s leadership team at turbulent time for his administration, according to people familiar with the changes.

Glen Shor, executive director of the Health Insurance Connector Authority, will replace Administration and Finance Secretary Jay Gonzalez as Patrick’s budget chief, and St. Elizabeth’s Medical Center president John Polanowicz will take over as secretary of health and human services, replacing JudyAnn Bigby, according to sources, including an administration official who confirmed Polanowicz’s appointment.

An administration source also confirmed that Patrick plans to name Suffolk County Sheriff Andrea Cabral to succeed state Public Safety and Homeland Security Secretary Mary Beth Heffernan. Slotting Cabral for the state post would enable Patrick to name an acting sheriff to serve until the next sheriff’s election in 2016.

Education Secretary Paul Reville also plans to step down before the start of the next legislative session in January, according to sources.

Patrick plans to announce the changes on Thursday, as well as his picks to replace the Cabinet members. All four departing members of the Cabinet have been with Patrick in some capacity since he took office in 2007.

Though Patrick’s leadership team has experienced turnover during his six years in office, never has there been as large an exodus at the same time. The changes in personnel come as his administration is dealing with midyear budget cuts, preparing a fiscal 2014 budget proposal, and coping with the fallout from scandals at a state-run drug lab and locally based pharmacy responsible for a nationwide outbreak of fungal meningitis.

The shakeup is certain to raise questions about Patrick’s agenda for the next two years as well as a possible brain drain from his administration as staff and appointed leaders, like Patrick, look at their own futures beyond 2014.

“The governor has the utmost respect for all his Cabinet secretaries. The folks we are bringing on to join the team are standouts in their field and top talents that will help the governor achieve an ambitious agenda,” an administration official, who would not confirm the four departures, told the New Service.

Following the November election, Patrick asked all his secretaries make a two-year commitment to the administration if they wanted to stay. The governor has made clear that he does not intend to seek a third term, and plans to return to the private sector.

Republicans have been calling for Patrick to remove Bigby for her handling of the Hinton drug lab fiasco that has results in more than 100 defendants being released from prison, suggesting they and the public have lost confidence in her ability to manage the executive branch’s largest agency.

Polanowicz, who has also served as president of Marlborough Hospital and vice president for operations at UMass Memorial Medical Center in Worcester, will inherit a Department of Public Health under intense scrutiny and the complicated task of helping to implement a new health care payment and care delivery reform law.

Energy and Environmental Affairs Secretary Richard Sullivan, Housing and Economic Development Secretary Greg Bialecki, Labor and Workforce Development Secretary Joanne Goldstein and Transportation Secretary Richard Davey all plan to remain in their posts.

The governor’s chief of staff, Mo Cowan, also recently announced that he planned to leave the administration for the private sector in January when he will be replaced by current communications director Brendan Ryan. Other staff changes have not been ruled out.