Barr is known for his expansive view of executive power and had previously sent an "unsolicited memo" to Rod Rosenstein criticizing special counsel Robert Mueller's ongoing Russian Federation investigation.
ABC News first reported Rosenstein's planned departure.
Deputy Attorney General Rod Rosenstein, a frequent target of President Donald Trump's wrath for appointing special counsel Robert Mueller and defending his Russian Federation probe, is expected to leave his position soon after Trump's nominee for attorney general is confirmed.
This claim has been somewhat corroborated by several other "legal sources" speaking to NBC news, who claim that the Mueller probe will conclude by mid-to-late February.
Rosenstein's decision to step down is a sign he feels comfortable about the integrity of the investigation, which many believe could be wrapping up soon (a federal grand jury working with Mueller was recently extended for six months). Lindsey Graham, R-S.C., on Wednesday, ahead of next week's confirmation hearing.
A person familiar with Rosenstein's thinking told HuffPost that there's now no concrete, specific plan in place for Rosenstein's resignation but said he's expecting to depart after Barr's confirmation.
There is no set timeline for Mr Rosenstein's departure, according to USA media.
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His charges consist of six counts of murder, two counts of attempted murder and eight charges relating to firearms offences. The 48-year-old Dalton answered "yes" to a series of questions, admitting that he shot eight people at three locations.
However Mr Rosenstein was stripped of the role late past year when Mr Sessions was forced out by the president.
Sen. Lindsey Graham (R-S.C.) told reporters that Barr talked to him about his relationship with Mueller, including the fact that their wives are in a Bible study group together and Mueller has attended two of Barr's daughters' weddings.
Barr wrote a memo in June critical of Mueller's potential investigation into obstruction of justice by Mr. Trump in firing former FBI Director James Comey.
He said it took about "three seconds" for him to get the answer he was looking for concerning what Barr thinks of Mueller.
"Much of the bad blood with Russia is caused by the Fake & Corrupt Russia Investigation, headed up by the all Democrat loyalists, or people that worked for Obama", the President tweeted in April. "I trust his judgement to find a worthy successor to Mr. Rosenstein".
Rosenstein has been a familiar face to viewers as he has occasionally had press conferences to announce the latest developments in Special Counsel Robert Mueller's investigation.
'He had absolutely no indication he was going to tell Bob Mueller what to do or how to do it, ' Graham said.