Republican presidential hopeful Ben Carson has said he does not see a path forward for his campaign after Super Tuesday's results.
The former neurosurgeon said he would make an announcement on Friday about the future of his 2016 bid for the White House.
Though he did not suspend his campaign, his statement on Wednesday signals the death knell for his bid.
He said he would not attend Thursday's Republican debate hosted by Fox News in his hometown of Detroit.
"I do not see a path forward for my campaign in light of last evening's Super Tuesday primary results," he said in a statement.
"However, this grassroots movement on behalf of 'We the People' will continue."
Mr Carson is due to speak at the Conservative Political Action Conference in Washington DC on Friday.
He was propelled to front runner status early last year only to steadily lose steam amid stumbles blamed on his political inexperience.
His withdrawal would leave four candidates vying to be the Republican nominee for November's White House election.
Mr Carson's statement comes as Republican leaders scramble to derail the momentum of their own front runner, Donald Trump.
Trump and Democratic candidate Hillary Clinton both had good nights on Super Tuesday as they claimed a number of wins.
Mr Trump had a big night translating his success in the polls to votes in the primaries as he won Georgia, Virginia, Vermont, Alabama, Massachusetts, Tennessee and Arkansas.
However, the party fears the pugnacious 69-year-old billionaire would be an electoral liability in an expected match-up against Clinton.
Florida Senator Marco Rubio, who won his first presidential state contest in liberal Minnesota on Tuesday, told Fox News the party would "never" unite behind Mr Trump.
The party's 2012 nominee, former Massachusetts Governor Mitt Romney, has scheduled a speech for Thursday about the state of the race.
Larry Donnelly, Law Lecturer at NUI Galway, says he doesn't "think there's any way" for the other Republican candidates to catch up with the billionaire front runner if he takes the 99 delegates in the Florida primary later this month.
