WASHINGTON -- President Barack Obama is preparing to nominate Mayor Julian Castro of San Antonio as his new secretary of Housing and Urban Development, elevating one of his party's Hispanic rising stars as part of a Cabinet shuffle that has possible implications for the 2016 presidential race, Democrats informed about the plans said Saturday.
Mr. Castro, who has often been mentioned as a potential vice-presidential candidate for the Democrats, would take the place of Shaun Donovan, who would become director of the Office of Management and Budget. That job is being vacated by Sylvia Mathews Burwell, who has been tapped by Mr. Obama to be secretary of Health and Human Services and seems headed to Senate confirmation.
Mr. Castro, 39, won national attention in 2012 as the keynote speaker at the Democratic National Convention, and he and his twin brother, Rep. Joaquin Castro, D-Texas, have become popular speakers on the party's fundraising circuit. Mr. Obama and the Democrats have predicated their future electoral hopes on appealing to the country's growing Hispanic population as House Republicans have blocked their efforts to overhaul the immigration system.
Mr. Obama's failure to push through immigration legislation has increased the political pressure on him and his Democratic allies from Latino groups that have demanded in recent weeks that the president act to reduce deportations that break up immigrant families. Mr. Obama has directed his secretary of Homeland Security to review deportation policy, but it is not clear whether the results of that review will satisfy immigration activists.
Mr. Obama had previously tried to lure Julian Castro to the Cabinet. After the 2012 election, the president approached the mayor about serving as Transportation secretary, but Mr. Castro indicated that he preferred to stay in San Antonio.
It is not clear what prompted Mr. Castro's change of heart about taking an administration post. He said in an interview last month that he did not feel that moving to Washington was in his best interest. He also passed on the chance to run for governor of Texas this year.
"Just like I decided not to run in 2014, I told the voters of San Antonio I would remain mayor until my tenure was over," he said. "So neither one of those was the right thing for me at that time."
Asked if he thought he might be wasting a political opportunity if he remained in San Antonio and did not move to the national stage in Washington, Mr. Castro said: "I'm going to be 40 this year. I feel like I have a decent amount of time either way. Whatever happens in the next two years to eight years, I'll have time."
But he has been advised to raise his profile in the hope of securing a possible slot on the national ticket. Democrats said that by taking an executive position in Washington, he would bolster his resume after serving as mayor of the nation's seventh-largest city since 2009.
"You take somebody who is a very successful and appealing politician who has regional strength and put them on the national stage, and by definition you raise their stature and increase the possibility that they are going to get a look by the nominee," said Jonathan Prince, a Democratic consultant.
In a move that raised eyebrows about his political future, Mr. Castro shared lunch in February with former President Bill Clinton and Henry Cisneros, a former San Antonio mayor who went on to serve as housing secretary in Mr. Clinton's Cabinet.
"I advised that he accept a position for President Obama," Mr. Cisneros said in an interview this year about the mayor's previous offer. "I thought that if he was going to be vice-presidential material in 2016, then he needed to be more than mayor at that time."
Few prominent Hispanic Democrats are positioned to be considered for vice president in 2016, but several Republicans are thought to be prospects for their party's next ticket, including Sens. Ted Cruz of Texas and Marco Rubio of Florida and Gov. Susana Martinez of New Mexico.
"That puts them in a bit of a pinch, and this may be an effort to move the pieces around on the chessboard," Danny Diaz, a Republican strategist who advises Ms. Martinez, said of the Democrats. "But it's not going to change that dynamic in just a couple of years."
Given how crucial their votes were in Mr. Obama's two presidential victories, some Hispanic Democrats believe that former Secretary of State Hillary Rodham Clinton, should she run and win the nomination, would be wise to pick a Hispanic running mate.
The San Antonio Express-News first reported that Mr. Castro had been offered a Cabinet post and was undergoing the standard background vetting necessary before any nomination, but the newspaper had not identified which position he would take. The Democrats who described the fuller Cabinet shuffle Saturday asked not to be identified because the plans had not been announced. The White House declined to comment.
The HUD job would become available to Mr. Castro with Mr. Donovan's move to the budget office, replacing Ms. Burwell. She would succeed Kathleen Sebelius, who announced last month that she was resigning as secretary of Health and Human Services after presiding over the disastrous rollout of Mr. Obama's Affordable Care Act in the fall.
Although not formally part of the statutory Cabinet, the budget office position has Cabinet rank under Mr. Obama, and its director can play an outsize if quiet role in shaping administration policy, regulations and spending priorities.