The historically large Democratic presidential primary field expanded again early Thursday.

Former Massachusetts Gov. Deval Patrick announced his entry into the Democratic primary in a video posted to Twitter.

“I am today announcing my candidacy for president of the United States,” Patrick said in the video. “Come be a part of this. We will build as we climb, to welcome other teachers and learners, other seekers of a better way and builders of a better future.”

A campaign spokesperson said in an email Patrick will make a campaign stop in Iowa “early next week.”

Mack Shelley, Iowa State professor and chair of the political science department said this late of an entry into the primary field is “unusual” but not entirely unprecedented.

Hubert Humphrey emerged with the Democratic nomination in the 1968 presidential election after a late entry into the race, though he did not run in any primaries or caucuses, Shelley said. Following his loss the party implemented a number of reforms to ensure more grassroots participation in choosing a nominee — including Iowa’s caucuses.

Patrick could tout his executive experience in government and his business experience during his campaign, Shelley said.

Since leaving the governor’s mansion Patrick has worked at Bain Capital, co-founded by ex-presidential candidate and current Sen. Mitt Romney, R-Utah.

“[Patrick] can market himself as the first black governor of Massachusetts, and therefore as someone with managerial executive experience in the public sector,” Shelley said. “I’m not sure if he would make major inroads to the African American base of support that Biden seems to continue to hold onto.”