WORCESTER – The top officer at Hanover Insurance Group Inc. is leaving the company after less than two years in the job to lead a health insurer based in California.

Joseph M. Zubretsky, 60, Hanover president and chief executive, will step down Nov. 3 to become president and CEO of Molina Healthcare Inc. of Long Beach, California.

He will be replaced by John C. Roche, 54, who has worked at Hanover since 2006 and most recently has been in charge of the insurer’s personal and commercial insurance business.

“Jack has been a key member of our leadership team for many years,” Kevin Condron, Hanover chairman, said in a news release. “He has played a critical role in the successful expansion of our company, working closely with the board and others, helping to position the Hanover over the past decade as the best partner for independent agents and one of the very best companies in our business.”

Before working at Hanover, Mr. Roche worked for St. Paul Travelers Companies. He is a director of the National Council of Compensation Insurance and has a bachelor’s degree from the University of Connecticut, Hanover reported in a news release.

Hanover is a property and casualty insurer, offering insurance coverage for homes, cars, boats and other property. The company posted net income of $155.1 million in 2016, down from $331.5 million in 2015.

Mr. Zubretsky took over as CEO in June 2016. He reorganized the company’s ranks of top executives, added $174 million to reserves as a buffer against claims and slashed about 160 jobs to cut expenses.

At Molina Healthcare, Mr. Zubretsky will run a health insurer that is grappling with slim margins and layoffs. With 4.7 million members and operations in 12 states and Puerto Rico, Molina Healthcare also has emerged as a significant insurer in some state health exchanges under the Affordable Care Act, or Obamacare.

Mr. Zubretsky was appointed CEO at Hanover after an extensive search for a new top executive to replace Frederick H. Eppinger Jr., who had led Hanover for more than a decade. The insurer's board decided against another search because it considered Mr. Roche the right person for the job, a spokeswoman said.