“When the initial rules came out with a focus on grass-roots fund-raising, of course our campaign was focused on the same thing,” he told reporters. “Now it sounds like there is a different focus and I do believe that we will qualify.”

Tom Perez, the chairman of the D.N.C., signaled in December that he would be willing to alter the debate criteria to allow Mr. Bloomberg to participate once primaries and caucuses began.

But he also said then: “Our logic for having a grass-roots fund-raising threshold was, it provides opportunity for people who don’t have the national name I.D. to get on the debate stage. If you want to win the presidency, you’ve got to connect with grass-roots America.”

Xochitl Hinojosa, a D.N.C. spokeswoman, argued Friday that the first two nominating contests would adequately measure the grass-roots enthusiasm around a particular candidate, and that the donor threshold was therefore unnecessary.

“Now that we will have the results of two elections and grass-roots support is actually captured in voting, that will replace the donor threshold,” she said.

During the fall and winter, as the D.N.C. began making it harder to qualify for the debates, some candidates who found themselves short of the thresholds began agitating for more inclusive rules.

Senator Cory Booker of New Jersey, for example, aired concerns about the diversity of the group that had qualified for the winter debates and led an effort to persuade Mr. Perez to make changes that would expand the roster. Mr. Booker dropped out of the race after failing to qualify for the debates held in December and January.