State treasurer Steve Grossman plans to tell delegates at the state Democratic convention this weekend that he is running for governor of Massachusetts in 2014.

“I think it will be clear, at the Democratic state convention in Lowell this Saturday, that I am running for governor,” Grossman told WSHM-TV in Springfield, where he was attending an elementary school groundbreaking.

The announcement is not a surprise. Grossman, a former chairman of the Democratic National Committee, has spent months laying the groundwork for a campaign and has acknowledged he was looking seriously at the Corner Office.

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He told the Springfield television station that his economic background will set him apart from rivals.

“Being governor of the Commonwealth is about leadership, and providing leadership that leaves no one behind,” Grossman said.

Grossman, who ran unsuccessfully for governor in 2002, will join a growing list of Democratic contenders. State Senator Dan Wolf, a founder of Cape Air, said today he is running for the job. Donald M. Berwick, former chief of Medicare and Medicaid in the Obama administration, is also running, as is Joe Avellone, a former Wellesely selectman.

Attorney General Martha Coakley is seriously consider a campaign. And Juliette Kayyem, a national security specialist and Globe columnist, has told Democratic officials she may run if Coakley decides against a campaign.