Former Massachusetts Gov.
Deval Patrick will test the waters in the 2020 Democratic presidential primary race.
He joins as crowded field with Joe Biden, Bernie Sanders, and Elizabeth Warren.
CNBC reports that some Democrats worry about the ability of current frontrunners to beat President Donald Trump.
Patrick was the governor of Massachusetts from 2007 to 2015.
His candidacy complicates life for Elizabeth Warren.
Her numbers in Massachusetts plummets with Patrick in the race.