A top administration official says Gov. Charlie Baker plans to file legislation that would allow thousands of state employees to retire early, and if that doesn't work, the state may resort to layoffs.

Baker's budget chief Kristen Lepore tells The Boston Globe the administration projects that 4,500 will take advantage of the early retirement program if it is passed by the Legislature, which would save $178 million in the fiscal year that begins in July.

Baker has projected the state's budget gap at $768 million, and lawmakers have passed a plan to close it through a series of cuts and other moves. The Massachusetts Taxpayers Foundation, a watchdog group, pegs the shortfall as high as $1.5 billion.

Baker has until Wednesday to file his spending plan for the 2016 fiscal year.