President-elect Joe Biden will nominate retired Army Gen. Lloyd Austin to serve as secretary of Defense, a source familiar with the process confirmed.

Austin would be the first Black Defense secretary in the United States. He previously served as the first Black chief of U.S. Central Command from 2013 to 2016.

Politico first reported Austin’s selection.

Biden has been under pressure to nominate a Black defense secretary, with Black leaders arguing he was falling short on diversity in his Cabinet as top positions filled up. Two other of the so-called “Big Four” Cabinet heads Biden has chosen are white: Antony Blinken as secretary of State and Janet Yellen as Treasury secretary.

With the Defense secretary chosen, only the attorney general Cabinet position remains open among the Big Four.

Spokespeople for Biden’s transition did not immediately respond to requests for comment from The Hill, but representatives for Biden’s transition team and Austin declined to comment to Politico.

Biden had said earlier Monday he would name his Pentagon nominee by Friday.

Michele Flournoy, who served as under secretary of Defense for policy, had initially been seen as a lock to be Biden’s Defense secretary, but the competition heated up the longer he went without naming his choice.

Flournoy would have been the first female Defense secretary. But in addition facing pressure to choose a Black nominee, Biden heard from a slew of progressives staunchly opposed to Flournoy.

Among other concerns, progressives cited her split with Biden to support a troop surge in Afghanistan during the Obama administration, her alleged support for selling weapons to the Saudis until relatively recently, her board position at defense contractor Booz Allen Hamilton and her co-founding of strategic risk consulting firm WestExec Advisors, which counted defense contractors among its clients.

Blinken is WestExec’s other co-founder, and several other members of the incoming administration also have WestExec ties.

In addition to Austin, members of the Congressional Black Caucus threw their support behind former Homeland Security Secretary Jeh Johnson, who also previously served as Pentagon general counsel.

But Johnson, who is also in the running to be attorney general, also faced concerns from progressives about his record on expanding family detention and accelerating deportations while at the Department of Homeland Security, as well as approving drone strikes targeting civilians.

Flournoy and Johnson have been notified they were not chosen, the source familiar with the process told The Hill.

Austin does not come without his own baggage. He also serves on a defense contractor board, Raytheon.

While serving as Central Command chief in 2015, Austin was shredded by lawmakers during a hearing over a failed $500 million program to train moderate Syrian opposition fighters to battle ISIS that only produced “four or five” fighters.

Perhaps most significantly, he has not been retired from the military for as long as the law requires a Defense secretary to be. The law mandates a seven-year cooling off period, and Austin retired in 2016.

Congress could pass a waiver for Austin like it did with former Defense Secretary James Mattis in 2017. But several lawmakers said at the time Mattis was a unique situation, as he was one of the military’s most respected leaders who lawmakers hoped would rein in President Trump’s most dangerous impulses.

Sen. Jack Reed (R.I.), the top Democrat on the Senate Armed Services Committee, warned in 2017 he would not support another waiver after Mattis.

“Waiving the law should happen no more than once in a generation,” Reed said. “Therefore, I will not support a waiver for future nominees. Nor will I support any effort to water down or repeal the statute in the future.”

The Hill