Earlier this month, Rosenstein told The Associated Press that "if anything that I did winds up being relevant to his investigation then, as Director Mueller and I discussed, if there's a need from me to recuse, I will".
It was Rosenstein who appointed Special Counsel Robert Mueller to take over the year-old investigation into Russian election meddling started by the FBI, in the wake of President Trump's decision to fire FBI Director James Comey.
According to Comey, Trump was referring to the FBI's investigation into Mike Flynn, who was sacked himself as national security adviser months earlier for allegedly lying to White House officials about his post-election contacts with Russian operatives.
Rosenstein is keenly aware that he could become a potential witness in the investigation.
One source said Rosenstein has yet to formally ask career attorneys inside the Justice Department for their opinion on whether he should recuse himself.
"He's furious at Rosenstein, but the list of his people who enrage him is ever-growing", a longtime Trump confidant, who recently spoke to the president, told The Daily Beast.
White House Staffers Are Reportedly Freaking Out Over Robert Mueller's Possible Firing
Comey testified in a Senate hearing last week that he believed he was sacked "because of the Russian Federation investigation". And since Attorney General Jeff Sessions has recused himself from the investigation, Rosenstein is acting in that capacity.
Rosenstein's comments weren't attached to any particular story, though the Washington Post had just reported that Mueller's probe had expanded and investigators were looking into the president's son-in-law Jared Kushner's business dealings.
And yesterday, The New York Times reported that Mr Trump's transition team had been ordered to preserve materials related to the ongoing investigations.
Brand was sworn in as associate attorney general on May 22. Now, ABC News reports that Deputy AG Rod Rosenstein, who replaced Sessions in supervising the Department of Justice's investigation into Trump-Russia collusion, knows that he might have to recuse himself, too. I felt, required it, ' Sessions said in testimony before the Senate Intelligence Committee this week.
Late Thursday night, he issued what many online are calling a "bizarre" statement, condemning recent reports. And there is no evidence that Mueller recommended to Trump that he fire Comey.
"Americans should exercise caution before accepting as true any stories attributed to anonymous 'officials, ' particularly when they do not identify the country - let alone the branch of agency of government - with which the alleged sources supposedly are affiliated", Rosenstein's statement said. "The Department of Justice has a long-established policy to neither confirm nor deny such allegations".
"She is also a dedicated public servant who is strongly committed to upholding the rule of law and our Constitution", he added.