First of Obama Cabinet nominees expected by January

FILE: Feb. 18, 2008: Sen. John Kerry and former Pakistan Prime Minister Nawaz Sharif followed by then-Sen. Chuck Hegel in Raiwand, Parkistan. (REUTERS)

President Obama is expected to make the first picks for his Cabinet and other high-ranking posts in the coming weeks – with national security nominees likely to be first.

Obama reportedly could name the next defense secretary by Dec. 31, with former Republican Sen. Chuck Hagel of Nebraska thought to be on the short list.

The nomination would likely follow those for secretary of state and Central Intelligence Agency director.

The president must make an unexpected change at the CIA, following the resignation last month of Director David Patraeus, the retired four-star Army general who quit last month after admitting to an extra-marital affair.

Obama immediately filled the position with then-Deputy Director Mike Morell. Though no names have emerged as a possible permanent replacement. Morell, who was acting director between Leon Panetta and Petraeus, is trusted and well respected within the administration.

“A slate of nominations could come soon,” a senior U.S. official told Fox News on Tuesday.

The most intriguing guessing-game on potential nominees appears to be who will be the next secretary of state when Hillary Clinton resigns as planned.

U.S. Ambassador to the United Nations Susan Rice was considered a front-runner. But Senate Republicans upset over her inaccurate statements following the recent deaths four Americans at the U.S. Consulate in Benghazi, Libya, appear likely to vote against her nomination.

The president last week commended Rice’s diplomatic work but has yet to make a decision, complicated by Democratic Sen. John Kerry’s purported interest in the post.

The senior Massachusetts senator is chairman of the Senate Foreign Relations Committee.

“I'm going to make sure that we've got a full national security team that can give me the best advice possible and do everything they can to keep the American people safe,” Obama said during an interview Tuesday with Bloomberg TV. “Susan Rice has done a great job as U.N. ambassador, but I haven’t made a decision about secretary of state.”

All of the national security choices will be viewed by U.S. allies and enemies as a sign on how Obama will pursue national security in a second term. All of his choices will be subject to Senate confirmation.

Other top names under consideration for defense secretary are Deputy Defense Secretary Ashton Carter, former top Pentagon official Michele Flournoy and Kerry, should Rice or somebody else get the post.

Hagel is co-chairman of Obama's Intelligence Advisory Board and teaches at Georgetown University’s Walsh School of Foreign Service.

The president could also have to fill the attorney general post should Eric Holder not stay for another term, with Homeland Security Secretary Janet Napolitano purportedly being considered for the promotion.

Among those considered likely to stay are Education Secretary Arne Duncan and Health and Human Services Secretary Kathleen Sebelius, who was key in helping the president pass his signature health-care reform law and is purportedly interested in helping him implement it over the next several years.

The Associated Press contributed to this report.