The former Massachusetts governor had staked his candidacy on a strong showing in neighboring New Hampshire. But Patrick struggled to get the kind of media attention needed to jump-start his longshot bid, falling well short of Democratic National Committee thresholds to qualify for a debate stage and running a barebones operation.

His exit leaves the primary field with only one candidate of color, Hawaii Rep. Tulsi Gabbard. And it comes just as the primary calendar shifts to feature a more diverse slate of Democratic voters in states like Nevada and South Carolina. Patrick's allies had begun to eye South Carolina and its large population of black voters in recent weeks as state where the former governor could do well, especially in the wake of former Vice President Joe Biden's early struggles in Iowa and New Hampshire.

Patrick is the third Democrat to drop out of the race after a lackluster showing in the New Hampshire primary, following Bennet and entrepreneur Andrew Yang.

In his announcement, Patrick urged supporters to "reject false choices" and work toward less partisan politics, while also warning against "poll-tested messages and cable news hits."

"Leaving room in our plans and our hearts for people who may not agree with us on everything is the only way to make lasting change. I don’t fit in an ideological box and most people I meet don’t either," he said. "We cannot, and will not, defeat Donald Trump by relying exclusively on old labels, poll-tested messages and cable news hits. We must meet people where they are and ask them to do the same for us."

He also used what was mostly an optimistic missive to take a shot at the press in his parting message to supporters.

“Many in the media have noted that I entered the race ‘late.’ As a direct and limiting consequence, I’ve met many people on the campaign trail who lament how they wished I had entered the race sooner,” he wrote, imploring voters not to “keep mistaking media narratives for political outcomes.”

He did not say Wednesday what his immediate plans were, nor did he endorse any of his former rivals. But he pledged to work to put a Democrat in the White House come next year.

"No one can stand on the sidelines at a time like this. I, for one, will not," Patrick said in his statement. "Failing to engage risks losing a lot more than an election next November."