Massachusetts Attorney General Martha Coakley (D) visits the Whittier Street Health Center, Wednesday, May 28, 2014. (AP Photo/Stephan Savoia)

Massachusetts Attorney General Martha Coakley holds a wide lead over her Democratic primary opponents in the race for governor, a new poll released Monday shows.

Coakley leads state Treasurer Steve Grossman 44 percent to 12 percent, according to the Suffolk University/Boston Herald poll. No other Democrat is in double-digits. Thirty-two percent of likely Democratic primary voters are undecided.

Coakely, a 2010 U.S. Senate candidate who ran a flawed, losing campaign against Republican Scott Brown, remains one of the most popular Democrats in the Bay State.

The primary is Sept. 9. In a general election matchup against Republican Charlie Baker and three independent candidates, Coakley leads Baker 36 percent to 29 percent.

Gov. Deval Patrick (D) is stepping down at the end of his current term.