Transit advocates were not surprised to learn General Manager Stephen Poftak would be leaving his job at the MBTA after four years at the helm, but they were surprised by the timing.

Advocates who GBH News spoke with said they expected Poftak to stay on until the new governor takes over in January, noting that would facilitate a smoother transition. And, they say, finding a replacement may prove difficult.

“He took a job that no one wanted, and he stepped into already tough circumstances,” said Stacy Thompson, executive director of Liveable Streets. “The problems with the T are problems that the governor and the Legislature created long before Steve stepped into that job.”

Poftak is the sixth general manager at the MBTA in the seven years since Charlie Baker became governor in 2015. Following a series of snowstorms which ground the transit agency to a halt, Baker created a Fiscal and Management Control Board, to which Poftak was appointed a member. He briefly was appointed interim general manager of the T in 2017 before Luis Ramirez was hired. But Ramirez was fired a year later when it was determined he couldn’t do the job. Poftak brought some stability to management serving four years one of the longest tenures in recent history.

And as much as Poftak stepped into difficult circumstances, recent issues with the T are likely to hamper the search for his replacement. Brian Kane, executive director of the MBTA Advisory Board, said the projected $200 million operating deficit, delayed delivery of new subway cars and the political spotlight on the T are all factors at play.

“There are good people out there,” Kane said, “but it will take a lot of convincing to get them to come here in the environment that the T finds itself in.”

Despite public perception of the MBTA, transit advocates said Poftak did his best in the role.

Joe Aiello, who chaired the Fiscal Management and Control Board, which oversees the MBTA, noted that Poftak organized a special panel to evaluate how the T could improve its safety culture — and that was three years before the Federal Transit Administration stepped in following a series of serious accidents.

Former Massachusetts Transportation Secretary Jim Aloisi said, in a sense, the story of the MBTA has come full circle since Gov. Charlie Baker took office eight years ago and was faced with a crisis at the agency.

“I don't think that Charlie Baker thought in 2015 that the T would be the front and center issue he'd have to deal with in the first few months of his administration,” he said. “And I think the new governor is going to find that the T once again is a front and center issue.”