(CNN) -- Newt Gingrich will end his bid for the Republican presidential nomination on Wednesday in Washington, D.C., a source close to the former House speaker told CNN.
Previous reports said Gingrich would likely quit the race on Tuesday.
Gingrich is expected to express his support for likely GOP nominee Mitt Romney. The two spoke by phone last week, a Gingrich spokesman said.
The decision to make the announcement this week was due to logistical reasons, sources told CNN last week.
Gingrich will leave the Republican presidential campaign with a mixed legacy.
The former speaker was left for political dead last year after his top campaign advisers quit over a disagreement on the direction of the campaign and its financial structure. But he came roaring back in late 2011 -- due in part to a Republican electorate that was not sold on Romney's candidacy.
It is the past few months, though, for which he may be most remembered -- for staying in the race for too long, rather than for the big ideas he espoused on the campaign trail.
For most, the time for him to go would have been after his Southern strategy failed, when he failed to win the Alabama and Mississippi primaries after coming out on top in South Carolina and Georgia.
Gingrich formally announced his bid for the nomination last May, only to see it almost crash the next month when a half-dozen staffers, including the senior leadership, left the campaign.
Among the gripes from the departed staffers was that it was difficult to schedule campaign events or spend the time needed to raise money to fuel the campaign. Additionally, there were complaints that Gingrich's wife, Callista, had veto power over all scheduling requests.
While his staffers felt Gingrich should be hitting the trail, he and Callista embarked on a two-week luxury cruise in the Mediterranean. For some in the campaign, that was the last straw.
His campaign languished over the summer and into the fall as conservatives test-drove a series of anyone-but-Romney candidates: first Michele Bachmann, then Rick Perry, then Herman Cain.
As his rivals rose and fell, Gingrich turned in strong performances in GOP debates -- which earned him a second look from those who were longing for an alternative to Romney, whose conservative convictions they questioned.
By December, polls had made Gingrich the front-runner with a double-digit lead over Romney.
But Romney, his supporters and Gingrich opponents went on the attack -- calling his consulting firm's work for the conservative-despised federal mortgage giant Freddie Mac "lobbying" and re-airing dirty laundry from his four decades in government.
After lackluster showings in Iowa and New Hampshire, Gingrich scored a double-digit win in South Carolina.
But then Romney's better-funded campaign, aided by friendly super PACs, crushed Gingrich in Florida and stopped his momentum.
Gingrich focused his campaign on the South and Super Tuesday. He won Georgia, which he represented in Congress for 20 years, but he couldn't pick up Tennessee. He went on to lose Alabama, Mississippi and Louisiana, which all went to Rick Santorum.
As Gingrich and Santorum continued to split the conservative vote, calls got louder for the former speaker to drop out and make it a two-man race between Santorum and Romney.
Santorum dropped out of the race earlier this month. With Gingrich formally on the way out, only Romney and Rep. Ron Paul of Texas are still in the race.