TOM GLYNN formally announced his resignation on Wednesday as the CEO of the Massachusetts Port Authority, putting one of the best jobs in state government up for grabs.

Baker administration officials were tight-lipped about who might replace Glynn, but initial speculation focused on two of the governor’s cabinet secretaries – Stephanie Pollack, the secretary of transportation, and Jay Ash, the secretary of housing and economic development.

Pollack would seem to be ideally suited, but sources say she is likely to stay on as transportation secretary if Gov. Charlie Baker wins a second term. Pollack oversees a vast transportation bureaucracy now and is very familiar with Massport, having previously worked as a consultant to Glynn, helping him develop a strategic plan for the authority.

Pollack issued a statement indicating she would not be a candidate for the job. “I am pleased by my appointment today to be a member of the search committee for a new Massport CEO. I look forward to working with other committee members to help identify qualified candidates for this important position,” the statement said.

Ash’s spokesman said he was not available for comment, but it’s no secret he’s interested in a new post. Whether Massport would be a good fit for him is unclear, and sources say there are other openings in state government that might suit him better.

Glynn’s decision to leave Massport was first reported by the Boston Globe. Glynn, 72, told CommonWealth he had been planning to leave for some time. Glynn was hired as Massport CEO in 2012 at the age of 66. He said he told Baker administration officials last year that he intended to leave after five years, but was asked to remain until after the election, which he agreed to do.

He gave Massport a 90-day notice on Wednesday, which means he will leave the agency on November 17. If no replacement is found by then, John Pranckevicius, the current chief financial officer, will take over and serve on an interim basis. Appointees of Baker control the Massport board.

Glynn has had an assortment of high-powered jobs inside and outside state government. He served as the chief operating officer of Partners HealthCare, the general manager of the MBTA, and the deputy US labor secretary under former president Bill Clinton.

The CEO’s job at Massport pays Glynn $300,000 a year. He oversees Logan International Airport, the port of Boston, Worcester Airport, and vast real estate holdings. The CEO manages operations that are vital to the state’s economy. At the airport alone, 20 new international nonstop destinations have been announced or started since Glynn took over. The number of international passengers at Logan has risen 65 percent since 2012.

“Throughout his tenure leading Massport, Tom Glynn has been a tireless advocate for furthering the Commonwealth’s reputation as an international destination,” Baker said in a statement. “Tom’s hard work to expand service at Logan and the Commonwealth’s other transportation hubs has driven economic activity across Massachusetts, and I thank him for his years of dedication and service.”