President Obama is expected to nominate former Republican Sen. Chuck Hagel as the next Defense Secretary, sources familar with the matter told CNN. The nomination is likely to occur early next week, other sources told CNN.

The White House told some senior members of Congress to expect the tapping of Hagel, according to a knowledgeable source. Another source with knowledge of the nomination called it “locked down.”

A Republican, Chuck Hagel represented the state of Nebraska in the US Senate from 1997 until January 3, 2009 when he retired.

The White House has previously said that the president has made no final decisions. One source told CNN Thursday that the president was “mulling” over appointments in Hawaii this week.

A White House source told CNN’s Wolf Blitzer the president “has not offered the job to anyone.”

In an interview that aired on NBC December 30, Obama allowed he had not then made a decision on who to nominate, but said in making the choice his “number one criteria will be who’s going to do the best job in helping to secure America.”

“I’ve served with Chuck Hagel. I know him. He is a patriot,” Obama said on “Meet the Press. “He is somebody who has done extraordinary work both in the United States Senate. Somebody who served this country with valor in Vietnam. And is somebody who’s currently serving on my Intelligence Advisory Board and doing an outstanding job. “

His comments came as Hagel has undergone criticism from high-profile figures in Washington and other groups taking issue with some of his past positions–namely, his former opposition to sanctions against Iran and comments he made that led some pro-Israel lobbyists to argue he was not supportive of the Jewish state. He was also not in favor of the surge of troops in Iraq pushed by the Bush administration.

“A lot of Republicans and Democrats are very concerned about Chuck Hagel’s position on Iran sanctions, his views toward Israel, Hamas and Hezbollah, and that there is wide and deep concern about his policies,” Republican Sen. Lindsey Graham of South Carolina said Sunday on Fox News.

The source with knowledge of the nominations adds that White House Chief of Staff Jack Lew is likely to be nominated as Treasury Secretary, perhaps as early as next week. This source says that while Lew is expected to be confirmed, there is some consternation in the business community about Lew, who is known as a “numbers guy” but has “little or no market and business experience.”

The administration is believed to be searching for a person with business expertise to run the Commerce Department, but there seems to be no first-in-line name circulating at this point. Gene Sperling is expected to stay as Director of the National Economic Council.

Former Washington state governor Christine Gregoire, former Ohio Gov. Ted Strickland and former Michigan Governor Jennifer Granholm are also being considered for cabinet posts.