White House press secretary Jay Carney said he didn't know if President Obama was aware that senior aides were weighing whether to replace Vice President Biden with Hillary ClintonHillary Diane Rodham ClintonClinton backs Georgia governor hopeful on eve of primary Pressure rising on GOP after Trump–DOJ fight’s latest turn Press: Why Trump should thank FBI MORE on the 2012 presidential ticket.

"I'm not aware that he was aware of it," he said at Friday's press briefing.

But Carney maintained that he "knew for a fact" Obama would have never seriously considered making the switch.

"Had anyone brought that idea to him, he would have laughed it out of the room," he said.

Carney, who served as a spokesman for Biden before becoming White House press secretary, said he didn't know whether Biden was aware that his place on the ticket was at risk.

The comments came in response to a New York Times report on a new book, "Double Down," written by journalists Mark Halperin and John Heilemann.

The pair reported that former Obama Chief of Staff William M. Daley, spooked by the president’s drooping poll numbers in fall of 2011, ordered campaign staffers to poll and focus-group the impact of switching Biden for the then-secretary of State. The aides then decided Clinton wouldn't give a big enough boost to the Democratic ticket to make it worth replacing Biden with her.

Carney noted that Obama viewed Biden as "an excellent partner."

"The role he played in 2012 — and you look at the job he did in his debate, I think there was little doubt he was an enormous asset," he said.

The same book also reported that Obama's relationship with former President Clinton were strained, and that the current president tired of Clinton's relentless appetite for political talk.

Carney said he wasn't "aware of" Obama ever complaining about Clinton, and said he was "enormously grateful for the advice and assistance" offered by the former president during the campaign.