PORTLAND — Buried in early campaign filings, a subtle shift has begun in the race for Maine’s next governor.

Democratic donors who rallied behind independent candidate Eliot Cutler in the last election have begun to send their checks instead to Democrat Mike Michaud, a five-term U.S. congressman. The small group of defectors includes Cutler’s former campaign treasurer and several high-profile Democratic fundraisers who helped generate tens of thousands of dollars for Cutler’s last gubernatorial bid, in part because they lacked confidence in that year’s Democratic candidate.

The Democratic divisions allowed Republican Gov. Paul LePage to eke out a victory in 2010’s three-way contest.

This year’s early defections, however, underscore what some Democrats hope will be a broad shift to unify behind Michaud next year to defeat LePage, a brash conservative whose first term has been marked at times by gaffes and low popularity.

“Democrats were split last time right down the middle. That’s just not going to happen this time,” said attorney Michael Asen, a Portland-based Democratic fundraiser who shifted his allegiance from Cutler to Michaud this year. “My highest priority is making sure we don’t have another four years of this governor.”

Asen, who host a fundraiser for Cutler before the last election, has already given Michaud $3,000 this year. He’s also organizing a group of lawyers to give more.

He is among more than two dozen former Cutler financial supporters who donated to Michaud once he began accepting donations in June, according to an Associated Press analysis of campaign finance reports. About half the group gave the maximum primary donation of $1,500, while some gave less than $100.

A Cutler spokesman dismissed the shift as “much ado about nothing.”

“I wouldn’t read too much into it 16 months out,” said Cutler spokesman Ted O’Meara. “What you have is professional Democrats supporting Democrats. It’s not like there were wholesale defections.”

At this point, the change is more symbolic than practical. Cutler, who has significant personal wealth, is expected to have the resources to run a competitive campaign in another three-way race regardless of whether he loses some financial backers.

Asen is not the most high-profile example of the shift.

Robert C. Monks served temporarily as Cutler’s treasurer before the last election. Monks now backs Michaud, and his wife, Bonnie Porta, serves as Michaud’s campaign treasurer. Together, the couple gave $6,000 to Michaud’s gubernatorial campaign, according to reports filed last month. And they’re working to generate much more from others.

“I felt like the Democratic candidate wasn’t running a very strong campaign last time, so I supported Eliot Cutler,” Porta said. “Mike wasn’t running in 2010 for this office. I don’t think anybody will work harder than him.”

Porta moved to Michaud’s camp along with Karen Harris, a top Democratic fundraiser from Cape Elizabeth. The women served as co-chairs of President Barack Obama’s Maine finance committee during the last election. Others who made the shift include former L.L. Bean chairman Leon Gorman, attorney Robert Gips and businessman Imad Khalidi, who continues to donate to Cutler but has given much more to Michaud.

Some prominent Democrats have stuck by Cutler, however.

Both of Cutler’s 2010 campaign finance chairs, Jean Gulliver of Falmouth and Marion Freeman of South Freeport, are returning. Both are Democrats who served on Obama’s last state finance committee. The Cutler fundraising team also includes prominent Republicans, such as Jim Nicholson, a former state GOP treasurer now serving as Cutler’s campaign treasurer.

Gulliver said she’s had conversations with Democratic colleagues who moved to Michaud’s campaign.

“Their philosophy is the Democratic Party is the most important entity for them. For me, it’s Maine,” she said, adding that she isn’t that concerned that continued Democratic divisions would allow LePage to win a second term.

“I trust Maine,” Gulliver said. “I trust people here to be sensible.”