Deputy Attorney General Rod Rosenstein is expected to leave his position after the Senate confirms President Donald Trump's pick for attorney general, William Barr, the Associated Press reports.

Rosenstein has protected the special counsel Robert Mueller's investigation into Russian interference in the 2016 election and the Trump campaign's possible involvement in it.

He hasn't set a specific date for his departure nor devised a formal plan for it, a source told the AP.

WASHINGTON — Deputy Attorney General Rod Rosenstein, who appointed the special counsel Robert Mueller and remains his most visible Justice Department protector, is expected to leave his position soon after William Barr is confirmed as attorney general, a person familiar with the plans said Wednesday.

Barr, who served in the position in the early 1990s and is President Donald Trump's pick to do the job again, has a confirmation hearing before the Senate Judiciary Committee next week and could be in place at the Justice Department as soon as February.

Robert Mueller formerly served as FBI director. Alex Wong/Getty Images

Rosenstein plans to leave at some point after that, though no date has been set and there is no formal plan for the departure, according to the person, who was not authorized to discuss internal conversations publicly and spoke on the condition of anonymity.

Mueller is investigating Russia's meddling in the 2016 election and contacts with the Trump campaign. Rosenstein and his chief deputy have continued to maintain day-to-day oversight over the investigation, a senior Justice Department official told reporters last month.

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Barr would take over control of the investigation, assuming the same final say over major investigative steps that acting Attorney General Matthew Whitaker has had since Jeff Sessions was ousted as attorney general earlier this year.

William Barr served as attorney general under President George H.W. Bush. Marcy Nighswander/AP

Barr has made critical comments of the Mueller investigation in the past, including an unsolicited memo he sent the Justice Department last year critiquing Mueller's investigation into whether the president had sought to obstruct justice by firing FBI Director James Comey.

At a news conference in December, Rosenstein said Mueller's investigation would be "handled appropriately" no matter who was overseeing it. He said Barr would be an "excellent attorney general when he is confirmed."

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Barr is expected to face questioning from Democrats about his views of the Mueller investigation at next week's hearing.

The departure is not unexpected. It is common for attorneys general and other cabinet secretaries to have their own deputies. Barr has told some people close to him that he wanted his own No. 2.