Confirming earlier expectations, US President Barack Obama has decided to nominate Senator John Kerry to replace Hillary Clinton as secretary of state, American media reported Saturday night. Clinton, who on Saturday fainted and sustained a concussion in the midst of a weeklong bout of stomach virus, is set to step down in the coming weeks.

Kerry, 69, is the senior Democratic senator from Massachusetts and the current chairman of the Senate Foreign Relations Committee. His candidacy for the US’s top diplomatic post gathered steam last week after the American ambassador to the UN, Susan Rice – who to that point was perceived as a frontrunner — withdrew her name.

Kerry’s nomination has been pushed back by a few days for reasons that include the need to finalize the process, other pending decisions of the cabinet, and the reaction to the shooting in Newtown, Connecticut, ABC News reported.

A native of Aurora, Colorado, Kerry was first sworn in as a senator in 1984. In 2004, he won the Democratic nomination to run for president, but subsequently lost to the incumbent, George W. Bush.

Kerry was an early backer of Obama and was under consideration to become his first secretary of state. He has been Obama’s envoy to hot spots such as Afghanistan and Pakistan, the administration’s point man in 2010 on a nuclear arms reduction treaty with Russia and a stand-in for Republican Mitt Romney during Obama’s debate preparation this year.

He has won praise from his Senate Democratic and Republican colleagues and should be confirmed easily.

Rice abruptly pulled out of the race on Thursday after a bitter, weekslong standoff with Republican senators who declared they would fight to defeat her nomination.

Rice had been widely attacked for a series of interviews five days after the Benghazi, Libya, attack that killed Ambassador Chris Stevens and three other Americans. Relying on intelligence community talking points, she attributed the cause to widespread protests throughout the Middle East over an anti-Muslim video rather than a terrorist attack by al-Qaida affiliates.

For the newly re-elected president, Rice’s withdrawal was a sharp political setback and a sign of the difficulties Obama faces in a time of divided and divisive government. Already, he had been privately weighing whether picking Rice would cost him political capital he would need on later votes.

When Rice ended the embarrassment by stepping aside, Obama used the occasion to criticize Republicans who were adamantly opposed to her possible nomination.

“While I deeply regret the unfair and misleading attacks on Susan Rice in recent weeks, her decision demonstrates the strength of her character,” he said.

Kerry, no stranger to the politicization of national security — he was the target of unsubstantiated claims by the Swift Boat Veterans for Truth over his Vietnam record — acknowledged his own experience in a statement praising Rice.

“As someone who has weathered my share of political attacks and understands on a personal level just how difficult politics can be, I’ve felt for her throughout these last difficult weeks, but I also know that she will continue to serve with great passion and distinction,” he said.

In tapping Kerry, the president will create a potential problem for Democrats by opening a Senate seat — one that recently defeated Republican Sen. Scott Brown is eyeing. Brown had been elected as Massachusetts’ other senator in January 2010 after Democrat Ted Kennedy died, stunning the political world as he took the seat held by Kennedy for decades. Brown lost that seat in the November election.

The Associated Press contributed to this report.