Progressive favorite Sen. Elizabeth Warren decided to pass on running for president in 2016, but she told the Boston Herald on Monday that she hasn't yet ruled out campaigning for Sen. Bernie Sanders.

"Too early to say," Warren, D-Mass., told the Herald when asked if she would campaign for the Vermont senator.

"Bernie's out taking about the issues that the American people want to hear about," Warren said.

She did not comment on whether Sanders, or other Democratic candidates like presumptive front-runner Hillary Clinton or former Maryland Gov. Martin O'Malley, were lobbying for her endorsement.

She also sidestepped the question when asked if Sanders can actually win, telling the Herald, "Bernie is there on the issues. That's what matters to a lot of people."

But she did say she is not surprised to see Sanders surging in the polls and drawing some of the largest crowds of any candidate.

"These are people who care about these issues, and that's who Bernie's reaching," she said. "I love what Bernie is talking about. I think all the presidential candidates should be out talking about the big issues."

The latest New Hampshire poll placed Sanders in a statistical tie with Clinton once the 5.2 percentage point margin of error was accounted for, reported The Hill.