Carson, the retired neurosurgeon who ended his own presidential bid earlier this month, will join Trump at a press conference at the businessman’s Mar-A-Lago resort in Palm Beach, Fla., to make the announcement.
Carson said earlier in the day in a Fox News Radio interview with John Gibson that he would be open to being an adviser for Trump.
"I'm willing to be an adviser to anyone who is going to have a significant effect on the future of our nation," he said.
Trump and Carson both have homes in West Palm Beach and proved to be friendly adversaries throughout the nominating process.
Their campaigns colluded at one point to seize the debate negotiating process from the Republican National Committee, and Trump went strongly after Ted CruzTed CruzThe 'Overton Window' and how Trump won the nomination with it Judge rejects attempt to stop internet oversight transfer Tech groups file court brief opposing internet transition suit MORE’s campaign for spreading the false rumor that Carson was dropping out of the race before the Iowa caucuses.
Carson rarely, if ever, criticized Trump while they were competing, and at debates, Trump repeatedly lauded Carson as a good and decent man.
Over the summer, Carson became the first Republican to challenge Trump atop the polls, putting an exclamation point on a cycle dominated by political outsiders and insurgent candidates.
While endorsements have the most part had little impact on the GOP race so far, Carson’s backing could help Trump on a number of fronts.
Carson will bring the energy of the tens of thousands of grassroots supporters that poured tens of millions of dollars into his campaign coffers. Long after Carson had become an afterthought in the GOP race, he continued to flirt with 10 percent support nationally in the polls.
Trump has so far done far better among evangelical voters than anyone expected, and Carson could help him solidify that base. He is still admired by many conservatives, who believe he handled himself with a quiet dignity throughout the campaign.
As the only black Republican candidate that ran for president, Carson could help Trump beat back criticism that Trump has failed to adequately repudiate white supremacist David Duke.
In Thursday's radio interview, Carson suggested that there are two versions of Trump.