In a sign that he may be conceding the support of Bronx Democrats in his bid for the mayoral nomination, the speaker of the City Council, Gifford Miller, stripped the borough of one of its committee chairmanships last week.

In a reshuffling of three council posts, the borough lost control over one committee while Brooklyn gained a committee. The changes were prompted by the departure of a Bronx council member, Jose Serrano, who won election in November to the state Senate.

Though it may be a minor, behind-the-scenes slight, political observers said Mr. Miller would bend over backward to secure endorsements from Bronx council members if he thought he had a shot. But with Fernando Ferrer, the former borough president of the Bronx, also running in the Democratic primary, Mr. Miller is expected to have a tough time making inroads there.

“He doesn’t have to give any little crumbs to the Bronx anymore because he feels that all of the council members are going to go with Freddy anyway,” one council staff member, who did not want to be identified, said.

Domenic Recchia Jr., who represents Coney Island and parts of Brighton Beach, was tapped to take over for Mr. Serrano as head of the council’s Cultural Affairs Committee. Mr. Recchia’s post as chairman of the council’s Small Business Committee is being assumed by a fellow Brooklyn representative, Michael Nelson. And, to complete the domino chain, Mr. Nelson’s job as head revenue forecasting, a finance subcommittee, goes to G. Oliver Koppell of the Bronx.

A spokesman for Mr. Miller, Stephen Sigmund, denied that the choices for the new posts were made with the mayor’s race in mind, or that the speaker was trying to curry favor with the Brooklyn delegation.

“From the council’s end, we don’t make any decision about committees and chairmanships based on what its political impact might be,” Mr. Sigmund said. “Decisions are made based on how the taxpayers of the city can be served.”

The council sent out a news release yesterday touting Mr. Koppell’s new title and saying he would be play a “major role” on the finance committee.

Last Wednesday, however, when the new posts were expected to be rubberstamped in committee, three members of the Bronx delegation protested because Mr. Koppell’s stipend was knocked down to $4,000 from the $10,000 his predecessor was getting.

The three members – the council majority leader, Joel Rivera; the Bronx delegation’s new head, Maria Baez, and a Democratic council member who has backed Mayor Bloomberg, Madeline Provenzano – did not mention the political subtext. And they said it was not the money, but the principle.

Mr. Rivera made a motion to split the package of changes so that members could vote in favor of granting their Brooklyn counterparts the new positions, but against the reduced stipend for Mr. Koppell. That motion failed, but Mr. Rivera – whose father heads the Democratic Party in the Bronx – and Ms. Baez met with Mr. Miller in private to hash out the problem. Mr. Rivera said he was told that the stipend reduction was standard because Mr. Koppell was a junior council member.

“It was bizarre in that you rarely see that behind-the-scenes stuff unfolding right on the council floor,” the council’s Republican Minority Leader, James Oddo, said. “But it’s not like a fiefdom.” He said one borough does not rule over a single committee for decades.

Indeed, as Mr. Recchia pointed out, the Bronx recently picked up the Parks and Recreation Committee, which is now headed by Helen Foster.

“This is not about Bronx, Brooklyn, or who’s going to win the mayor’s race, it has nothing to do with that whatsoever,” Mr. Recchia said. “This is not the speaker playing politics.”

Mr. Koppell, a former state assemblyman and attorney general, did not attend Wednesday’s hearing. On Sunday, he told The New York Sun that he never discussed the stipend with Mr. Miller and he declined to discuss the larger political implications.

“The speaker indicated to me that, as chairman of this subcommittee, that I would be, in a way, the no. 2 person on the finance committee and I would be part of the budget negotiations team, and I was very pleased with that,” he said during a phone interview.

Others say the changes allow Mr. Miller to reward Mr. Recchia for loyal support, and will help the speaker garner primary votes in Brooklyn, an area two other Democratic opponents, Rep. Anthony Weiner and Council Member Charles Barron, represent.

The Bronx and Queens have several plum committee appointments because they helped elect Mr. Miller three years ago to his role as speaker. Though Brooklyn has a larger delegation, it is usually fractured and has historically been left without key committees as a result.