According to the Globe, she will formally announce her decision Monday.
Coakley, who has served as the state's attorney general since 2007, ran an unsuccessful Senate campaign in 2010 against Republican Scott Brown. Brown, who lost his Senate seat to Elizabeth Warren (D) in 2012, has said he will not run for governor in 2014. Brown, however, is exploring a 2016 presidential bid.
Several Democrats have already jumped in the race, including state Treasurer Steven Grossman and state homeland security official Juliette Kayyem. Rep. Michael Capuano (D-Mass.) is also expected to make a decision soon on whether he will run. On the Republican side, Charles Baker announced his candidacy earlier this month. Baker previously ran for the office in 2010. Independent candidate Evan Falchuk is also pursuing the office.