Democratic gubernatorial candidate Jay Gonzalez picked up a key endorsement this week — one that will help him consolidate support among the lefty grass roots that have emerged as a significant force within the Massachusetts party in the last several years.

State Senator Jamie Eldridge of Acton, one of US Senator Bernie Sanders’ most prominent supporters in 2016, threw his support to the former Patrick administration budget chief, claiming he would be a “transformational governor.”

“He is a bold progressive Democrat, who has laid out a vision of investing in our communities, including education, making progress on social justice, including criminal justice reform, dramatically improving our state’s entire transportation system, and making health care a right in Massachusetts,” Eldridge said.


The endorsement comes at a critical time. Early next year, Gonzalez and his rivals — Newton Mayor Setti Warren and environmental activist Robert Massie — will make their cases at the local Democratic caucuses that choose delegates for the party’s endorsement convention in June.

Doug Rubin, who served as Patrick’s chief of staff as well as his senior political strategist, said Eldridge’s endorsement is a boost for Gonzalez because of the senator’s standing among the state’s Our Revolution activists who have been organizing around issues and candidates since the 2016 elections.

“Senator Eldridge’s endorsing Jay is one of the bigger things to happen in this race so far,’’ said Rubin, who has not taken sides in the Democratic primary race. “He is well respected by progressives across the state.”

Frank Phillips can be reached at frank.phillips@globe.com.