The veteran public health official at the forefront of Cook County’s response to the coronavirus crisis was handed a pink slip Friday, prompting surprise and concern from some county commissioners who said they thought he was doing a good job.

No official reason was given for Dr. Terry Mason’s departure, but Cook County Board President Toni Preckwinkle said he was terminated.

Adding to the day’s drama, Cook County Health announced Friday that it would close the emergency department at Provident Hospital for about a month starting Monday to figure out a better way to handle the “large volume of patients” and “challenges of a pandemic” at the South Side hospital.

Mason joined Cook County Health as the system’s chief medical officer before transitioning into the role of chief operating officer of the Cook County Department of Public Health, which is part of the health system, in 2013.

Before going to work for the county in 2009, the former Mercy Hospital and Medical Center urologist spent nearly four years as Chicago’s public health commissioner. For decades, he was host of WVON-AM’s radio talk show “Doctor in the House.”

Debra Carey, the interim CEO of Cook County Health, said in a statement that Friday was Mason’s last day.

Doctors Kiran Joshi and Rachel Rubin, who have both been senior medical officers at the county department since 2014 and members of the medical staff at Stroger Hospital, have agreed to step in and co-lead the department effective immediately, Carey’s statement continued.

“On behalf of the Cook County Health Board of Director and the staff, I want to personally thank Terry for his years of service to the residents of Cook County,” Carey said in the statement. “He has been a valued member of the executive team and has contributed to our success in recent years.”

Mason was one of the main faces of the county’s response to coronavirus, though Joshi and Rubin have been “deeply involved in public health’s response to the coronavirus since the beginning and have my full support and deep gratitude,” Carey said in a statement.

Mason is the third highest ranking health official to be cut from county government in recent months. In November, the Board of Cook County Health voted to oust Dr. John Jay Shannon, the CEO of the county’s health arm.

In February, the health system’s chief financial officer, Ekerete Akpan, was dismissed.

Cook County Commissioner Larry Suffredin, D-Evanston, said he hadn’t been given a “coherent” explanation for why Mason was let go, saying all of his experiences with the former head of the public health department in the past 10 days had been positive.

“I always felt Terry Mason did a good job, and I always enjoyed working with him, but obviously Debra Carey and [chair of the health system’s board of directors] Hill Hammock felt it was time for a change,” Suffredin said.

Commissioner Sean Morrison, R-Palos Park, found the move “very alarming” considering the spread of coronavirus throughout the county.

“This coronavirus is very real, we haven’t even hit the apex yet, that’s a few weeks away,” Morrison said. “I think he did a good job.”

Preckwinkle said she has great confidence in Carey as well as the new leadership team but couldn’t comment further as it was a “personnel matter.”

The Public Health Department is part of the Cook County Health System, a $2.8 billion operation that oversees Stroger and Provident hospitals as well as health care at Cook County Jail and other county sites.

At Provident, Cook County Health officials announced they will work on ”reconfiguring the current the flow of patients, increasing space between patients and creating and equipping areas to function as isolation areas” because the hospital was not designed to handle “a large volume of patients or the challenges of a pandemic involving a highly contagious disease,” a release announcing the move said.

Because of those changes the hospital will be closed starting April 6 and will likely remain closed until May 6, though officials hope to reopen sooner.

The limitations of the current emergency room were part of the decision to construct a new facility, though those plans are currently on hold.

Medical personnel will be temporarily reassigned to Stroger or other places in the county’s health system to assist with the response to coronavirus.

Patients who come to the hospital during this time will be triaged and either directed to a nearby hospital, Stroger Hospital or seen by a physician at Provident, the release said.